About Semi-Precious Gemstones – Yorkshire Jewellery Company

About Semi-Precious Gemstones


About Amber

Found all over the world, Amber is a fossilised tree resin.
Resin is present in trees , and protects them as it prohibits insects from burrowing into the bark. When this protective resin is produced in large quantities it seeps out of the bark, and hardens to become copal. Those pieces of copal get buried in the soil and gradually harden over millions of years to become Amber.
Both Copal and Amber are light in weight, this leads to them being carried great distances often far away from their origins.

Most Amber hails from the Baltic regions of Northern Europe.
However Amber can be found all around the world.

Amber often appears on the beaches of Eastern coasts of England where it has been washed ashore by the sea.

Blue John

About Blue John

Blue John which is also known as Derbyshire Fluorspar, is a semi precious gemstone mineral, a unique form of fluorite with distinctive bands of a purple, blue and yellowish colouring, found only in Blue John and Treak Cliff Caverns, Castleton, Derbyshire. Blue John is a heavily crystallised formation and occasionally surface marks can be seen. This is not detrimental to the stone and in fact enhances its individuality. It has been seen that certain specimens of Blue John show signs of fluorescence on exposure to ultraviolet light, but this is the exception rather than the rule.

The gemstone is the most highly prized ornamental variety of Fluor-Spar (Calcium Fluoride), differing from any other variations of flour-spar due to its unique crystal structure, and banded veins of colour which run through the stone. During the 18th and 19th centuries Blue John was mined for its ornamental value, producing exquisite bowls, eggs and goblets. 

Splendid unique specimens of Blue John stone can be found in collections throughout the world. The mines are sadly now largely extinct, however, small veins and nodules of fine quality Blue John stone of sufficient size for jewellery can still be found. 

Lapis Lazuli

lapis lazuli



Whitby Jet

Whitby jet originally was in the form of monkey puzzle trees about 180 million years ago during the Jurassic period. As the trees eventually died some of them were taken into the water of rivers and eventually ended up in the sea. The trees then would become engorged with water and sink to the bottom of the sea. Over a period of time they would be covered by thick layers of sand and mud, which  compressed the trees under the sheer weight of the water above. This enormous pressure of the sea over the millions of years caused what was the monkey puzzle tree to become the material we now call jet.


Jet is found in small deposits around the world, in countries including the UK, France, Germany, Spain and the USA. Deposits vary in quality from region to region, largely dependent on the levels of trace elements such as aluminium, silicon and sulphur.

Whitby Jet can be found on the a 9 mile stretch of coast from Boulby to Robin Hoods Bay.

Whitby Jet is considered to be the best in the world due to the high levels of aluminium and this produces Jet of extremely high quality.


Whitby Jet has been used in the manufacture of jewellery and tokens since the bronze age.

Since that time a wide range of items have been made from the material from Roman medallions to Victorian mourning rings and on to the modern silver and Jet items popular today. After a long history, Whitby Jet is once again the jewellery of choice and none more so than the original Victorian pieces.

Whitby Jet was much favoured by the Victorians as a material for the manufacture of beautiful jewellery. With its light weight, deep black lustre and warm touch to the skin it was both practical and elegant.

During the reign of Queen Victoria protocol dictated that only Jet jewellery could be worn at court during periods of official mourning. This royal endorsement confirmed the status of Jet as the material of choice for mourning jewellery and fuelled the expansion of the Jet industry in the late 1800’s. Never was this more so than in the period following the death of Victoria’s husband Prince Albert from typhoid fever in December 1861.