Monday, 30 January 2017

He clasps the crag with crooked hands; Close to the sun in lonely lands, Ring’d with the azure world, he stands.



Excerpt from The Eagle- Alfred Lord Tennyson
Published: 1851
Lapis Lazuli- (also known as lazurite and ultramarine pigment)
Have you ever visited the British Museum? There are hundreds of exhibits featuring ancient items of jewellery, many of which use Lapis Lazuli, a distinctive deep blue stone, in their design. In ancient times Lapis Lazuli was highly desirable, difficult to obtain and a symbol of wealth and prosperity, so only the most privileged could afford it. These days lapis lazuli is still a popular, relatively inexpensive, semiprecious gemstone used in modern jewellery.  Many of the ancient designs wouldn't look out of place in todays world.
The finest Lapis Lazuli is an intense blue and the word ‘azure’ that describes the deep blue colour of this stone has found its way into many languages. In Poetry, azure is often used to represent or refer to the sky or Heaven.

The name originates from the latin for stone “lapis” and the Persian "Lazhward", which was an area, known for its deposits of lapis lazuli (“stone of Lazhward”) Lajward.

Lapis Lazuli is a metamorphic rock composed of sodium, calcium, aluminium, silicon, sulphur, oxygen (Empirical Formula: Na3CaAl3Si3O12S). It is formed when limestone or marble, deep in the earth, has been subjected to extreme heat and pressure sufficient to change the chemistry of their constituent minerals. The result is the formation of the blue silicate lazurite, the distinctive blue component of Lapis Lazuli. Lapis often contains visible white calcite and golden grains of pyrite that mimic gold.

Image of Lapis Lazuli taken at the Natural History Museum
Colour: Deep azure blue to light blue, bluish green. (Hex: #26619c) (RGB: 38, 97, 156)
Hardness: 5.5-6

Lapis Lazuli was treasured by ancient civilizations and used for ornamental carvings, mosaics, wall coverings and it was fashioned into beads or cabochons and polished to use as a gemstone. In ancient Egypt it was used to carve scarabs, protective stones or amulets in beetle form that protected graves, houses or were given as a gift.


This lapis lazuli scarab has a hawk-head figure wearing a ram's-horn crown carved into the back. In his left hand is a staff from which a lotus blossom dangles. 4th century BC.
Scarabs were a common type of amulet, seal or ring bezel found in Egypt. They were made in the shape of the sacred Scarab beetle.

The Royal Cemetery of Ur is an archaeological site in southern Iraq (ancient Mesopotamia) which was excavated between 1922 and 1934 by Leonard Woolley in association with the British Museum and the University of Pennsylvania. The site contained a wealth of treasures amongst more than 2000 burials which took place between 2600 BC-2300BC. Especially significant was the Tomb of Queen Puabi, which was discovered relatively untouched, her body was covered in jewellery made out of beads of gold, silver, lapis lazuli, carnelian and agate. Many of these items are on display at the British Museum.
Exhibit 121412 at the British Musem

Drinking tube; consists of alternating gold and lapis lazuli cylinders enclosing a long silver tube; 

silver had perished and has been restored. Approximately 2600 BC- 2300 BC.Royal Cemetery (Ur).
Exhibit 121486 British Museum
Diadem (headband worn by royalty) consisting of 14 gold pendants attached to a band of three strings of in total 173 beads of lapis lazuli (84), cornelian and other stone beads, carved, perforated and polished. Approximately 2600 BC- 2300 BC. Royal Cemetery (Ur).
Exhibit 122324 British Museum
Choker; a neck ornament of triangular gold and lapis lazuli beads; three string holes. 

2600BC Royal Cemetery (Ur)
Sapphires were not known before the Roman empire and many scholars agree that lapis lazuli is actually the stone meant for the term “sapphire” in the Bible.  
Pliny the Elder (a Roman author and naturalist) described Lapis Lazuli in his work The Natural History, “For sapphiros, too, is refulgent with spots like gold. It is also of an azure colour, though sometimes, but rarely, it is purple;" 
Roman
Engraved Gemstone with Mercury (Hermes)
First–third century CE
Lapis Lazuli
Indiana University Art Museum, Burton Y. Berry Collection, 64.70.49


This is an example of a Roman Lapis gemstone carved with an image of Mercury the messenger of the gods. 
Early references to the mining of lapis lazuli were in Persia, Tibet and China. Today it is still mined in varying qualities in the former Soviet Union, Asia, South and North America and Africa. However, the finest quality stone comes from the mines in Afghanistan in the remotest area of north-eastern Afghanistan. In the mountains of Badakhshan, is the mine Sar-i Sang (a name meaning "place of stone"). It is estimated to be 7,000 years of age and believed to be the oldest continuously-operating mine in the world. Throughout recorded history, people have come here seeking lapis lazuli, which exists here in the purest form and in the greatest quantity known on Earth.

Take a look here at a short video about the mining of Lapis, a highly risky occupation with little reward for the miners.

Ultramarine

In the past Lapis was ground and processed to make the pigment ultramarine for tempera paint and oil paint. The name “Ultramarine” is derived from the Latin “ultramarines”, meaning "beyond the sea" as it was originally imported from Asia by sea. 
Vincent Van Gogh – Starry Night

The painting was investigated by the scientists at the Rochester Institute of Technology and the Museum of Modern Art in New York. The pigment analysis has shown that the sky was painted with ultramarine and cobalt blue.
The earliest use of lapis lazuli as a pigment were found on the cave paintings of the Temples of Bamiyan in Afghanistan, dated to be from the 5th and 9th centuries A.D. 


To produce the pigment from lapis lazuli, the blue lazurite has to be separated from the other minerals present. Lapis Lazuli was ground and mixed with molten wax, resins and oils, wrapped in a cloth and kneaded with a caustic solution called lye to isolate the blue particles from the rest of the mixture. It was an expensive colour to purchase because of the very high quality of stone required and because of the drawn out complicated method of extraction. The use of Ultramarine with gold in medieval times was popular for use in sacred paintings and manuscript illuminations. 




Miniature of Christ in glory holding a globe and blessing the Virgin illuminated by Pacino di Buonaguida, central Italy (Tuscany), c.1335 -c.1340

European artists used the pigment in moderation, reserving the ultramarine blues for the robes of Mary and the Christ child. As a result of the high price, artists sometimes economised by using a cheaper blues, such as azurite, for under painting.

In 1806 the chemical composition of ultramarine was identified and in 1828 a process to manufacture a synthetic ultramarine which could be made economically was discovered. The first artist accredited with its use was J.M.W. Turner in 1834 and from then on nearly all of the pigment used in painting was of the synthetic variety.

Imitations

Gilson LapisA synthetic simulation of Lapis Lazuli has been created using the Gilson process. Although Gilson Lapis may look similar to Lapis Lazuli, it is not made of the same composition, lacking the natural random patterns displayed in most true Lapis Lazuli.

Swiss Lapis- Jasper that is dyed blue to simulate Lapis Lazuli.
Howlite- may also be dyed an ultramarine blue to simulate Lapis Lazuli.



Treatments/enhancements-

The colour of Lapis Lazuli is natural and it is generally not treated, though occasionally lighter coloured stones may be dyed a deeper blue.

Similar Minerals
Azurite crystals on display at the Natural History Museum (found Chessy, Rhone, France)
Azurite-  is a common mineral found in many locations worldwide. Areas that produce excellent crystals include in France, Italy, Russia, Morocco, Namibia, the United States, Mexico, Australia, and China. Azurite is a much softer mineral but can be used for jewellery such as beads and cabochon, however, heating destroys azurite that limits its uses. Azurite was also used as a blue pigment since antiquity and was a major source of the blues used by medieval painters. Whilst true lapis lazuli was chiefly supplied from Afghanistan, azurite was a common mineral in Europe at the time. 

Sodalite- is sometimes confused with lapis lazuli. Some specimens have a similar colour and the presence of white veining is found in both materials. Sodalite is named in reference to its sodium content. It is used for carvings and some jewellery pieces.
Hardness: of 5.5 to 6.

What to look for when choosing Lapis Lazuli Items


Mined Lapis Lazuli rough pieces can be very large and the larger sized pieces are often carved into objects of art. A good lapidarist can shape and size smaller pieces for use in designer jewellery.
The most valued colour in a lapis lazuli is the azure blue of mid to dark tones with no visible specks or streaks of white calcite and little or no pyrite, although many prefer lapis with an even sprinkling of golden pyrite flecks.
Vintage 1950s Mid Century Tiffany & Co. Lapis Lazuli & Diamond Cocktail Ring in 18ct Yellow Gold

Avoid lapis that looks dull and green, this is the result of an excess of pyrite. Lapis with white calcite streaks is less attractive and therefore of less valuable.



Looking after your Lapis Lazuli Jewellery.
  • Remove jewellery when undertaking activities such as sports, swimming, gardening etc. 
  • Remove jewellery when sleeping. 
  • Don't allow jewellery to come in contact with chemicals, chlorine is particularity damaging. Rinse off any chemicals that come into contact with your jewellery straight away. 
  • Remove jewellery before bathing and apply lotions and perfumes before putting on your jewellery. 
  • Store jewellery items separately so that pieces do not tangle, rub or scratch against each other. Use a soft lined (satin or velvet etc) case or bags. 
  • If you need to clean your lapis jewellery use a mild soap and soft cloth. Avoid mechanical cleaning, such as steam or ultrasonic systems and chemical solvents.
  • Threaded beads should be checked periodically to ensure the thread is still in good condition, get re-strung when necessary.







l

Tuesday, 29 March 2016

All that glisters is not gold; Often have you heard that told:

All that glisters is not gold;
Often have you heard that told:
The Merchant of Venice- William Shakespeare


The Latrobe nugget, 717 grammes of crystallised gold
discovered in Australia 1853

Gold (Au) is a highly sought-after rare metallic element. Pure gold has an attractive bright yellow colour. Gold is a soft metal and is often alloyed (combined) with other metals such as silver, copper, nickel, and zinc to make it more durable and change the colour. It is non reactive to air and water and malleable making it ideal to been used for jewellery, money and ornamentation symbolising wealth and prosperity.
Like other precious metals, gold is measured by troy weight and by grams. When it is alloyed with other metals the term carat (or karat in the USA) is used to indicate the amount of gold present. Pure gold is twenty-four twenty-fourths (24/24ths) gold, and is called 24-carat gold. Gold that is 18-caret gold is eighteen twenty-fourths (18/24ths) gold and six twenty-fourths (6/24ths) other metals. 
Carat Percent Gold Hallmark
24- 100% gold -N/A
22- 91.6% gold -916
18- 75% gold -750
14- 58.5% gold -585
9- 37.5% gold -375

Alloys added to colour gold.
yellow gold- silver copper

white gold- zinc, copper, tin and manganese
rose gold- copper and silver
green gold- high proportion of silver or cadmium
blue gold- iron 
grey gold- iron
Plan A
For hundreds of years alchemists toiled in their laboratories to produce a mythical substance known as the philosopher’s stone. The stone was said to enable, as well as immortality and other phenomenon, chrysopoeia- the transmutation of base metals such as lead into gold.
The Famous Philosophers Stone
(not really, artistic impression)

Famous alchemists included Sir Isaac Newton and Nicolas Flamel. The alchemists were working on the theory that lead and gold were compounds, the periodic table wasn't to be developed for hundreds of years. They did not know that lead and gold were different elements.
Amazingly in 1980 scientists succeeded in turning bismuth (next to lead on the periodic table) into gold – all you need is a particle accelerator and a vast supply of energy. Sadly the amounts produced were negligible and with a cost of more than one quadrillion dollars per ounce, (in the USA a quadrillion is 1,000,000,000,000,000. or 1015not at all feasible, the current price is $1,220 per ounce approx.

Plan B
If you can't make gold, make something that looks like gold.

Pinchbeck
Is an alloy of Copper and Zinc made to imitate gold. It was developed at a time where the only legal standards of gold were 18ct and 22ct and before many of the worlds largest gold sources were discovered. Gold was an expensive purchase and 9ct carat gold was not introduced as a legal standard until 1854. It was invented by a London clock maker Christopher Pinchbeck (1670 to 1732 approx.) It had a bright gold colour that didn't fade or rust and was much more affordable than the real thing. This early Pinchbeck was beautifully created and finished to imitate fine jewellery and was used as "traveling jewellery" by the rich at risk of robbery from highwaymen and thieves. Such was its success that many tried to copy and these poor imitations led to Christopher's son, Edward Pinchbeck putting an advert in the Daily Post of July 11, 1733, headed "Caution to the Publick." in attempt to protect his business and reputation. He shrewdly kept the “recipe” and method of production a secret in his life time so only he could make the metal. The material is thought to be three parts zinc and 4 parts copper and possibly with a slight wash of gold on the surface to prevent tarnish.
click here to buy this Georgian, pinchbeck cuff bracelet.

The of fame Pinchbeck spread to France and the alloy was in considerable demand and again subject to imitation. A Lille jeweller called Rentz, created a similar alloy but it it didn't keep its colour. It was perfected by a jeweller named Leblanc, who managed to produce a good imitation named "
similor". It proved to be so popular that the goldsmiths of the day started legal proceedings about its use. The result was that the alloy was only allowed to be used for such things as shoe buckles, buttons etc so as not to compete with the regular goldsmith's work. Old texts refer to other alloys that were used to imitate gold including Mannheim or Dutch Gold, Prince Rupert’s Metal or Prince's Metal, Tombac. Pomponne is the name given to all the different alloys with a copper base that imitate gold. Alloys bearing a close resemblance to Pinchbeck continued to be used well into the nineteenth century until the process of electro-gilding made it easy and cheap to deposit a layer of gold on any metal as required.
The term pinchbeck has become to mean sham, spurious, or counterfeit and is often associated with fake jewellery. Ironically, Pinchbeck Jewellery is once again sort after and highly collectable and the consumer has to be wary that they are in fact purchasing real Pinchbeck and not an imitation.


Gilding
Gilding is the process of applying a fine layer of gold to the surface of a less valuable material. It is an ancient skill and in the British Museum are silver nails with gold foil wrapped around the top. These were used to secure gold foil on a frieze in the Temple of the Eyes at Tell Brak one of the great cities of northern Mesopotamia (now known as Northern Syria) and estimated to be from early in the 3rd millennium B.C. Examples remain of the Egyptians using gold foil to adorn wood and metal in tombs, coffins, sarcophagi and other objects. There are also Egyptian paintings that show goldsmiths making the foil. Initially the foil was wrapped around the objects then techniques developed to attach the gold to the substrate such as burnishing (polishing to create a smooth surface) and using adhesive from animals or vegetable such as egg white.
The Romans also used gilding and Pliny the Younger in his writings discusses the costliness of using mercury in the gilding process. But by the 3rd and 4th centuries AD the use of mercury had become the standard method and would remain so up to 19th century.
Mercury gilding of metals was a hazardous process and was replaced by electrolytic gilding when electrical batteries were invented in the early 1800's.


Elsewhere
In ancient South American a method called electroless gilding was used. They used the natural electrochemical potential difference (the exchange of electrons between substances) of gold and copper to obtain thin gold deposits from gold solutions on their jewels or ritual objects. A technique that is still used in the electronic industry. They also invented depletion gilding- a technique to produce a high-purity gold surface by removing everything that is not gold. Tumbaga- was an alloy of gold, copper and silver used extensively by Pre-Hispanic American metal smiths. Its relatively low melting point and malleability made it ideal to be made into detailed objects. The alloy could be made to look like pure gold by treating the finished surface by etching (applying an acid solution) to dissolve the copper and then hammered or burnished to join the gold, creating a uniform gold surface.
A tumbaga pendant: male shaman holding rattles, from Panama; circa A.D. 700 to 1500.


Powder Gilding
Gold foils or leaves were ground into a fine powder which was then mixed with a binder and applied to a surface. 

Ormolu is the finish used on decorative mountings of furniture, clocks, lighting devices, chandeliers and porcelain to imitate gold. The manufacture of true ormolu used a process known as mercury gilding or fire gilding. A solution of nitrate of mercury was applied to a piece of copper, brass, or bronze, followed by the application of an amalgam of finely ground gold and mercury. The item was then heated over an open fire until the mercury burned off (creating toxic fumes) the gold remained, adhered to the metal object. The process was repeated several times until a thick enough layer of gold had been created that could be left mat or was burnished with a heliotrope stone. Most mercury gilders died by the age of 40 due to exposure to the harmful mercury fumes.
 "Hang him; a gilder that hath his brains perished with quicksilver is not more cold in the liver".—John Webster, The White Devil, 1612.
Because of the impractical cost and health risks ormolu pieces were no longer produced after the early 1800s.
1812 Rare English Ormolu and Marble Mantle Clock


Bronze Doré The French referred to ormolu as bronze doré.

Gold Leaf Gilding
Gold Leafing or mechanical surface gilding is a technique of bonding very thin sheets of pure or nearly pure gold to a surface. Gilding was used for books, religious objects, pottery and ornaments. The use of real gold as well as imitation gold leaf (Dutch leaf) was common throughout Europe from the early middle-ages forward.
Mechanical surface gilding involves the use of a special adhesive called gold size, this can be either water or oil based. The surface to be gilded needs to be prepared and primed. Then an even coat of gold size is brushed onto the surface to be covered and left to dry to the correct tack (degree of stickiness) for the gold leaf to adhere to. The gold leaf is laid on the prepared surface usually with a soft brush, then gently pressed onto the surface, it is not cut to size first as it only adheres where the size has been applied. When the size has fully hardened the applied gold leaf can be burnished to a smooth finish to bring out the lustre of the gold leaf.
Using a non-gold leaf has been around since at least the 1500’s as a decorative replacement for costly gold. There are a number of different types of imitation leaf including:
  • Abyssinian Gold (alloy of copper and tin).
  • Ducat Gold (alloy of copper and aluminium).
  • White Metal (alloy of copper and aluminium).
  • Dutch metal (alloy of copper and brass).

Dutch metal leaf is by far the most common alloy used in gilding and is still commonly employed for gilding today.

Keum-boo (Korean for attached gold) is an ancient Korean gilding technique still being used in Jewellery making today. Pure gold and silver have similar atomic structure and heating them and applying pressure allows an exchange of electrons between the metals and creates a permanent bond. This technique depends on the surface having a layer of fine silver before heating and applying thin sheets of gold to the silver, to make silver-gilt. This technique is used in many cultures, including Chinese, Japanese and in the West to bond gold to other metals, including iron, copper, aluminium, gold alloys, white gold, palladium and platinum. 
click here to see  modern Keum-Boo


Gold-Plated Jewellery
Electroplating is the process of using electrical current to coat an electrically conductive object with a thin layer of metal. For gold plating it involves passing an electric current through a solution (electrolyte) containing gold dissolved as microscopic atoms. Two electrodes are submerged in the positively charged electrolyte (also known as plating bath) and connected to a circuit with a power supply. The object that is to be electroplated is connected to the negative terminal of the power supply (known as the cathode) a piece of gold is connected to the positive terminal (known as the anode). As the electricity flows through the circuit the electrolyte splits up and some of the gold atoms it contains are deposited in a thin layer on top of one of the cathode and gold atoms move from the anode into the electrolyte. 
When the item is new, the colour of the gold plate is similar with real gold jewellery. Normal electroplating for jewellery puts a layer of between 1 to 20 microns of gold on to the base metal. The plating is not permanent and can rub off, the thicker the plate the longer it lastthe item can be re-plated. Plating can come in a variety of colours.
Vermeil
Gold vermeil is a form of plating where the base metal must be sterling silver, the gold layer must be 14ct or higher in purity and the thickness of the gold layer must be at least 2.5 microns. 
Gold-Filled Jewellery
Gold-filled jewellery is also known as "rolled gold" or "rolled gold plate." It is created by using heat and pressure to fuse a layer of gold to copper, brass or some other base metal. The bond produced is a permanent one. In order to be considered gold filled, the gold content must be 5% or 1/20 of the total weight. It is marked rolled gold plate, R.G.P., or plaqué d'or laminé.
Bonded Gold
Bonded gold jewellery is when a thick layer of gold allow is bonded to a base metal or sterling silver core, so that the item is about 10% gold by weight. The bonded gold layer must be at least 9ct gold, this also applies to gold plated and rolled gold items in the UK. 

Hallmarking
In 2012 the British Hallmarking Council (BHC) clarified the legal position on marking bonded gold, rolled gold and gold plated products.

"The BHC further stipulates that, assuming the core is 925 ie Sterling Silver, the article should carry a full silver hallmark, or a 925 stamp if it is under the Hallmarking exemption weight for silver of 7.78 grams. Bonded Gold on a base metal core cannot be hallmarked. No stand-alone gold fineness marks will be permitted on bonded gold articles, because they are potentially confusing and misleading to UK consumers. It is not permitted additionally to mark the article 9k, 10k, 14k, 18k etc, as is common practice in the United States.
The only circumstance in which this is allowed is if the gold fineness is immediately preceded or followed by the words ‘bonded gold’, ‘rolled gold’ or ‘gold plated’. For example, an article with a silver hallmark (or 925 stamp on underweight articles) can be marked as follows ‘925 & 18ct bonded gold/rolled gold/gold plated’.
It is also emphasised that the bonded gold layer must be of a fineness of at least 375 parts per thousand and of a recognised in UK standard. So, for example, ‘bonded gold’ of apparently 10K can only be described as 9 carat. This follows the practice for gold plated and rolled gold articles in the UK.
The guidance applies to all bonded gold, rolled gold and gold plated silver articles below the 7.78 gram exemption weight for hallmarking, as well as for those requiring hallmarking. The exemption is an exemption from hallmarking itself, not from the requirements of every other part of the Hallmarking Act 1973."

Visit the London Assay Office

A note about Fools Gold.

The gold colour, metallic lustre and weight of Iron Pyrite meant it could be mistaken for gold by the inexperienced. Pyrite and gold do often form together and some pyrite deposits contain enough gold to justify mining. Marcasite jewellery is actually made from Iron Pyrite or Fools Gold. It does not actually contain the mineral marcasite. Pyrite was set into other metals to produce a sparkly effect.


Wednesday, 18 February 2015

Dr. Evil: When I ask for sharks with frickin' laser beams on their heads, I expect sharks with frickin' laser beams on their heads!

Dr Evil making demands in Austin Powers International Man of Mystery.
You can buy shark laser pointers online.

Newly acquired in our Jewellery Workshop  - A Laser Welder - not attached to a sharks head but positioned on a workbench.
The word laser started as an acronym for "Light Amplification by Stimulated Emission of Radiation" Amazingly the concept was first proposed in 1917 by Albert Einstein but didn't became a reality until 1960. You can read here about the history of Lasers, its not clear cut who the actual inventor is but Theodore Maiman made the first laser operate on 16 May 1960 at the Hughes Research Laboratory in California.
A Jewellery Laser Welder uses light energy that produces heat to weld metals. The heat from the welder is finely focussed in a narrow beam, so that the surrounding area is not effected or discoloured by the process. Argon gas is used to shield the surrounding area and reduce oxidation and if Laser filler is used make that flow smoother. This makes lasers particularly useful for:
  • Repairing damaged jewellery without the need to unset and then reset heat sensitive stones. 
  • Pieces can be repaired with only localised heating preserving the appearance of the item.
  • Rejoining areas that are particularly hard to get to.
  • Ring resizing.
  • Retipping and repairing claws.
  • Repairing costume jewellery.
  • Repairing filigree pieces.
  • Repairing items that contain epoxy resin, enamel or pearls.
Can be used on platinum, palladium, gold, silver, titanium and other jewellery metals.


Our new Laser Welder in action

Read on for a more detailed explanation of Lasers.

Lasers are described as powerful narrow, monochromatic, coherent and directional beams of electromagnetic radiation (EMR), that can travel long distances with out diffusing. 
Electromagnetic radiation is a form of energy that can travel without a medium like air or water to travel through. EMR can take several forms including heat, visible light, ultra violet, x-rays, radio waves and gamma rays depending on the type of atom and the amount of energy applied. Radiation may be thought of as energy in motion. In Lasers, atoms are made to absorbs energy causing them to jump up to a higher level called an excited state, this in turn causes electrons within the atoms to move and release photons. If photons pass close to another atom the other atom may emit a photon and if that photon passes yet another atom, that atom might also emit a photon. So the number of photons increases very quickly. Lots of photons create electromagnetic waves and as these photons all have the same specific frequency and polarity the photons are precisely in step giving coherence to laser beams. Coherence is a fixed relationship between the phase of waves in a beam of radiation of a single frequency. Most light beans consists of many waves travelling in roughly the same direction but the photons are randomly distributed causing the light to diffuse. Click here to see a clear example of coherent and diffuse light.
Within a Laser Welder electrical energy is used to stimulate the atoms within a confined space. Mirrors are used to bounce photons back and forth passing atoms on the way causing yet more photons to be emitted. This stimulation of the atoms rapidly creates light amplification.The front mirror is semi-reflective so some of the photons escape creating the beam which in this case is intense and hot enough to weld metals.

Other uses for lasers -
There are several different types of lasers,
 the most powerful lasers can quickly cut through solid rock or metal sheets. Some use gases such as helium, neon, argon, and carbon dioxide. Lasers also use semiconductors (Galiodium and Arsenic), solid-state material (ruby, glass) and even chemicals (hydrofluoric acid) in their operation. Some, like the ruby laser, emit short pulses of laser light. Others, like helium-neon gas lasers or liquid dye lasers emit a continuous beam of light.


image courtesy of S McGill
Some everyday uses of lasers- bar code readers, DVD's, measuring equipment, favoured weapon of aliens, eye surgery, cancer treatments, tattoo removal, laser light shows, pointers, atomic clocks to name a few.


Laser Light Show

We have been using lasers at Maker Mends for many years in another capacity.
We use barcodes to track items as they are progress from one department to the other. All Items booked into our system are given a bar coded label then we use a laser barcode scanner to scan items as they move round the building. 
Most barcode scanners consist of three different parts including the illumination system, the sensor and decoder. The sensor in the barcode scanner detects the reflected light from the red light and generates an analog signal that is sent to the decoder. The decoder interprets that signal, validates the barcode using the check digit then coverts it into text.
This converted text is delivered by the scanner to a computer software system holding the relevant information. This system is known as automatic identification and data capture (AIDC).
Bar codes first were used on Wrigley's chewing gum in June 1974.

Laser scanner in use in our office






Wednesday, 12 November 2014

“I certainly don’t believe in returnism, as it were,” he said. “I don’t think that’s sensible.”

David Cameron's interesting excuse on why he doesn't think the Koh-i-noor diamond shouldn't be returned to India. 
Jewellery and gem stones are often objects of dispute and the ownership decided in court, here is a small selection.
The Koh-i-noor diamond currently on display at the Tower Of London
This ancient diamond, the Koh-i-noor, first recorded in 1306 has a considerable history , known to have come from one of the earliest regions in the world to mine diamonds; the Golconda Kingdom in India.  It was originally 793 carats when uncut. It has never been sold but possession gained in the course of rebellions, wars, invasions and uprisings. You can read more here. In 1849 the British Empire's East India Company confiscated the Koh-i-noor Diamond as compensation for the Sikh wars and presented it to Queen Victoria. Despite repeated requests for its return to India, it remains in the Tower of London as property of the British Crown and is currently set in the Maltese Cross at the front of the crown made for Queen Elizabeth the Queen Mother and can be seen in the Tower of London.
Actress Linda Christian and husband Tyrone Power
Someone who did believe in "returnism" was actress Linda Christian (1923- 2011), albeit with a little financial sweetener. She is credited with being the first ever Bond Girl - “Valerie Mathis” in a TV adaptation of Ian Fleming’s first Bond novel, Casino Royale, in 1954. She was married to the movie star Tyrone Power in 1949, they had two children together before their divorce in 1956. In 1955 she was given a gift of jewellery from an admirer, socialite Robert H Schlesinger, however the cheque for $132,000 that he had given to Van Cleef and Arpels of New York as partial payment bounced. She refused to return them stating they were a christmas gift. However, lawyers managed an amicable agreement where Ms Christian returned the jewellery and was given an undisclosed sum for the "inconvenience".
A pensive Princess Diana wearing a Tiara
What about when a gift only means a loan - a newspaper article from May 6th 1996 reports how Princess Diana being increasingly frustrated by the delay in her divorce from Prince Charles, threatened to sell some of her jewellery. She believed that as they were given to her as gifts at her wedding they belong to her, however the Queen insisted that as they were Royal Heirlooms they must remain with the Royal Family. The items included a tiara estimated at the time to be worth £2 million. She was protected by British Law regarding her famous engagement ring. The UK legislation under Section 3(2) of the Law Reform (Miscellaneous Provisions) Act 1970 (2) states that the gift of an engagement ring shall be presumed to be an absolute gift; this presumption may be rebutted by proving that the ring was given on the condition, express or implied, that it should be returned if the marriage did not take place for any reason. On the 13th of July 1996, almost 15 years after their wedding Diana and Charles announced that they had finally reached an agreement on the terms for their divorce, including Diana being given the right to keep all the jewellery bestowed to her.


Some of Imelda Marcos's baubles
How about you pilfer from your countries treasury and use the funds to purchase high value properties, works of art, jewellery as well as a large shoe collection for yourself, to whom does that jewellery ultimately belong? Imelda Marcos, wife of Ferdinand Marcos (president of the Philippines)  as well as her amazing shoe collection amassed a huge collection of jewellery known as The Roumeliotes, Hawaii and Malacanâng Collections. In February 1986 Ferdinand Marcos was ousted in a "People Power" revolution. Ferdinand and Imelda along with their family and entourage scarpered to the U.S.A. It was reported that U.S. Customs agents discovered 24 suitcases with gold bars and diamond jewellery hidden in them and in addition, certificates for gold bullion valued in the billions of dollars were allegedly among the personal properties.
Philippine investigators estimated their wealth over £6.2 billion.
The next president, Corazon Aquino, set up a special commission to recover these funds for the treasury - but now, more than 25 years later, just over £2.5 billion has been accounted for. Imelda's jewellery had been languishing in a bank vault for decades after being seized. The Sandiganbayan, the Philipine court, in January this year forfeited in
favour of the Philippine government the Malacanâng collection of former First Lady Imelda Marcos. In its ruling, the court said this collection is also part of the ill-gotten wealth of the late deposed President Ferdinand Marcos and his family. However, the Marcos's are now disputing the ruling, The heirs asked the court that they be given ample opportunity to prove that the jewellery may have been lawfully acquired through other means or acquired prior to the late dictator’s tenure, so the fight continues...
See some of the collection here



The disputed Bahia Emerald

Heard of the Bahia Emerald? A 3ft tall, 840lb rock embedded with 9 large emerald crystals ranging in size from 220mm, 140mm, 130mm, 110mm down to 37mm -  weighing 180,000 carats in total. It was discovered at the Bahia mine in Brazil back in 2001. Valued at nearly £250 million it has had a remarkable journey, transported to the USA, hidden in an abandoned petrol station, stolen, recovered, submerged in a vault during hurricane Katrina, used as collateral in a diamond deal and at one point even put up on Ebay with a buy now price of £45 million – bargain!.
Legal possession of the Bahia Emerald has changed hands several times, according to some reports, the Bahia Emerald was even involved in a $197 million banking transaction with the notorious Bernard Madoff before he was arrested for committing the largest financial fraud in U.S. history.
At one time eight individuals laid claim to the Bahia Emerald, now just two claimants remain awaiting yet another judgement.
The National Geographic Channel have made a documentary about it and there is also a book available. Read more here 


The Aurora Pyramid of Hope - can be seen at the Natural History Museum

Aurora Pyramid of Hope
On permanent loan in “The Vault” at London's Natural History Museum is the Aurora Pyramid of Hope. A display of 295 differently coloured diamonds, 267 carats in total. Only 1 in 10,000 gem-quality diamonds is coloured. The collection was put together over a period of 25 years by two New Yorkers  - Alan Bronstein and Harry Rodman. Named after the Aurora Borealis for the colours and Aurora the Roman goddess of the dawn to symbolise a new beginning and to protect our natural heritage for the future. After the death of Mr Rodman aged 99, it became the subject of court battle between the 2 families. In 2001, at 92, married Mr. Bronstein’s 81-year-old mother, Jeanette, his longtime friend and neighbour, it was she who introduced Harry to her son Alan, and then further complicated by the fact that Mr. Rodman made seven wills in the last decade of his life. In their lawsuit, several of Mr. Rodman’s heirs — a grandniece and four grandnephews — argue that the Bronsteins took advantage of an elderly man and duped him into signing away his interest in Aurora Gems for $10,000. They tried to prove that Jeanette Bronstein had married Harry Rodman for his money. A lawyer who drew up Mr. Rodman’s wills testified on Mr. Bronstein’s behalf stating that “Harry described him as a friend and the son he never had", the judge ruled in favour of Alan Bronstein. The Rodman heirs plan to appeal the decision.