"But, strangest of all, the very instant the shore was touched, an immense dog sprang up on deck from below,

as if shot up by the concussion, and running forward, jumped from the bow on the sand. Making straight for the steep cliff, where the churchyard hangs over the laneway to the East Pier so steeply that some of the flat tombstones, thruffsteans or through-stones, as they call them in Whitby vernacular, actually project over where the sustaining cliff has fallen away, it disappeared in the darkness"

Bram Stoker describing the moment Dracula, in the form of a large dog, arrived on the shores of Whitby. You can take a walk around Whitby and follow in Dracula's footsteps, click here.

Whitby Parish Church with the ruins of the Abbey in the Background
and a vampire bat flying by............

As well as the infamous Dracula, the cold waters and shallow bays of the North Sea make for good Whitby Oysters and the other product of Whitby that is of interest especially to the Jewellery Trade is Whitby Jet. Jet is soft and easy to carve- 2.5-4 on the Mohs scale, light - specific gravity of 1.30-1.35  and can be highly polished to give it an intense black colour that never fades; making it ideal for jewellery.
Imagine a time where what was to be the British Isles, was located further south in the area that Northern Spain and Portugal are located. Much nearer the equator with a warmer, humid climate with Dinosaurs such as Megalosaurus going about their daily lives. The land was  covered in trees, the dominant species was a conifer  - the Araucaria very similar to the Monkey-puzzle tree or Chilean pine (Araucaria araucana) we see today - this was Whitby during the early Jurassic period  -  approximately 180 million years ago.

The prehistoric looking Monkey-puzzle tree
or Chilean pine (Araucaria araucana)

As the trees died and fell they would often be swept into rivers by flood waters. Travelling downstream eventually being deposited in the sea at the Yorkshire Basin. The water-logged timbers sunk into the sea floor, where the conditions - lack of oxygen led to a prolonged breakdown of the wood into a pulpy mass. This was then covered with sediments (sand, mud and organic remains) and the accumulated weight this and the sea water exerted a huge pressure. Over the millennia this pressure combined with chemical reactions resulted in the flattening, compressing and fossilisation of the wood into a tough compacted shales known as jet-rock. So basically Jet is fossilised trees and as is it is formed from an organic substance, it is not a mineral but a mineraloid (a mineral-like substance that does not demonstrate crystal or ordered formation). If you examine jet under a microscope the annual rings of the original wood can be seen.
Jet is found in two forms, hard and soft. Hard jet is the result of the carbon compression and salt water - soft jet is the result of the carbon compression and fresh water.
Jet has been used since prehistoric times to make jewellery. Whitby being the source of high quality hard Jet, however Jet it is also found throughout the world, Russia, Turkey, Germany, France, Spain, Portugal and North America - although not all of it is the hard jet. 
Meanwhile back in ancient Whitby - as the centuries passed Jet bearing shale was exposed by the natural erosion of the coastline depositing pieces of jet along the beaches. This gradual weathering of the shale banks provided a good source of Jet for the Bronze age craftsmen and then the Romans, Anglo Saxons, Vikings. 
In ancient times jet jewellery was an indicator of status and was also used in amulet jewellery - (amulets were worn protect its wearer from danger or harm). Bronze Age burial sites throughout the UK have been found to contain all kinds of objects carved from Jet such beads, buttons, earrings and belt-sliders.
The necklace below is made from Whitby jet and cannel coal was found in a burial site at Killy Kiaran in Argyll. It was an expensive item - imported from Yorkshire sometime between 2050 and 1800 BC.

The necklace consists of six decorated jet spacer plates, a triangular fastener of cannel coal and numerous beads, mostly of jet. The estimated original number of beads is 114.

The Romans made extensive use of jet during their 367 year occupation (43AD to 410AD) with Roman jet workshops situated in York, using Whitby jet to create ornaments and jewellery that were exported throughout the Roman Empire.  Excavations of Roman sites all over Britain have unearthed such artefacts such as rings, bracelets, necklaces, pendants, dagger handles and hairpins and when excavating the foundations of an old railway station in Eburacum (the Roman name for York) a Roman jet workshop was discovered containing tools and half worked pieces as well as articles of jewellery. The raw jet came from the Whitby area and the finished pieces included a number of pendants depicting Medusa's head.

 Jet Medusa medallion found in a  Roman grave in Bensozia (Roman Colchester)
thought to protect the wearer from the "evil eye"

After the Roman deserted England, it was the turn of the Anglo Saxon invaders to settle here, followed by Vikings and then the Normans. 

7th Century Gold and Jet Pendant

The use of jet wasn't so popular in these times, but the introduction of Christianity during the Anglo Saxon period saw jet being used mainly for ecclesiastical jewellery such as crosses, rosaries and rings. 

This medieval cross of Whitby Jet was found in a North Yorkshire Garden

The earliest record of jet as an occupation are in local Whitby records where it is mentioned in the year 1598 that a John Carlill's occupation was a "jet worker".

In the early 1800s, the use of jet for jewellery and ornaments began to rapidly increase in popularity. Jet workshop were set up in Whitby and by 1851 there were fifty workshops.  At the great Exhibition in London in1851 a Whitby jet carver Isaac Greenbury displayed his work and this led to commissions from the Empress of France and made a jet chain 6 feet 4 inches long to the order of the Queen of Bavaria.
With the death of Prince Albert in1861, Queen Victoria went into mourning only wearing black. Whitby jet provided the ideal material for her mourning jeweller and for a few years was the only jewellery allowed in her Court. 

Victorian Mourning Brooch

Victorian Cameo

Also at this time the Victorian seaside holiday became popular and the new railway brought in the holiday makers eager to buy the latest fashion. The industry went into a boom period; at its height there were over two hundred jet workshops in Whitby and fourteen hundred men (from a population of four thousand) were employed in Jet related trades such as mining. Up to this time jet was retrieved from the beaches but the demand in Victorian England was such that small mines were dug into the hills. No explosives were used for the danger of damaging the jet, but the pieces were dug out using picks. The jet was cut into manageable sizes and although originally carved by hand only, in the early 1800s mechanical means of turning, cutting and polishing Jet were used. A special mud from Derbyshire was used to polish the jet. The very final polishing was carried out with rouge, a fine iron oxide powder using wheels made of wool, walrus or porpoise hide. Final finishing was carried out on a wheel made of chamois leather.

The popularity of Jet declined by the end of the 19th century and now there are only a handful of skilled local craftsman capable of producing Whitby Jet Jewellery. Whitby is proud of its Jet Heritage and there are many examples of the amazing carvings at the Whitby Museum  and at the Whitby Heritage Centre there is an actual victorian jet workshop that was discovered, sealed away in the attic of a house and only discovered when the building was sold and going to be renovated.
Jet has had a minor resurgence in popularity with the Goth subculture and Whitby hosts the annual Whitby Goth Weekend where participants fashions are influenced by the Victorian era and the favourite colour to wear is black.
Its still possible to pick Jet up from the Beach at Whitby but be careful of the high tides!
The hard part is to carve the jet into jewellery probably better to buy a piece from the few remaining jet shops. 

How to care for your jet; jet can be safely washed in a mild detergent and warm water. Remember jet is relatively soft and can easily be scratched so prevent it rubbing against other items, store wrapped in tissue.

Often other materials are used to imitate Jet - such as black glass, plastics and in the past vulcanite - although this is now itself collectable. 

To authenticate jet remember:

Jet is light
Jet is warm to the touch.
Jet leaves a brown streak when stroked across unglazed porcelain( like the back of a tile)
When burnt with a red-hot needle, jet smells like coal. 
If polished jet exhibits a static electricity charge.

Jet will look hand carved and not cast.
Jet is black.
It may contain imperfections such as cracks and small inclusions.