Gemstones C - K
Carnelian is a type of translucent chalcedony which owes its red colour to the presence of iron oxide. It can be uniformly coloured or banded. Carnelian has been valued since ancient times and was used in signet rings by the Greeks and Romans. It can be found in USA, Brazil and India and has a hardness of 7.
A rare mineral found in Siberia. It varies in colour from purple to lavender with a swirling, pearly appearance. It has hardness of 5-6.
A translucent variety of chalcedony, varying in colour from yellowish green to apple green It can be found in Australia, Russia, Brazil and USA. Chalcedony has a hardness of 7.
Flourite is widely occuring and can be many different colours including green, purple or yellow, the colour being determined by the presence of certain trace elements.
It was extensively mined for ornamental use in Castleton, Derbyshire in the nineteenth century. This particular variety of flourite was named Blue John.
It occurs in many different places in the world, including USA, Mexico, China and Canada. It has a hardness of 4.
Not a gemstone at all, but made from colourless glass containing tiny particles of copper. It was discovered in Italy in the seventeenth century and has been often used in jewellery. Not to be confused with sunstone which is a natural gemstone. Blue goldstone is made from blue glass.
Also known as hematite, it is an important iron ore which can be found in many different forms, including crystals. It can be found in USA, Ukraine, India , China and parts of South America. It has a hardness of 5-6 .
Howlite is usually white, sometimes with darker veins running through it. It can be used to make cabochons and gemstone beads in its original form or it can be dyed blue as a substitute for turquoise (turquinite). It can be found in in USA, Canada and Germany and has a hardness of 3.5.
Iolite is a blue variety of the mineral cordierite. It can be found in India, Sri Lanka and Myanmar and has a hardness of 7- 7.5
The name jade is applied to two seperate minerals - jadeite and nephrite.
Jadeite has a more granular texture and occurs in a wider range of colours than nephrite. Jadeite is a rarer stone than nephrite and is more valuable. It has a hardness of 6 - 7 and can be found in Myanmar, USA and Japan.
Nephrite has a fibrous, silky texture and can be white through to green in colour. It is a tough stone and is particularly good for carving. Nephrite has a hardness of 6.5 and can be found in USA, China, Canada and New Zealand.
A blue green vitreous mineral, gem quality material can be found in Brazil, USA and Switzerland. It has a hardness of 3 - 6.