There are a few more quartz that I want to discuss. The first is the tiger’s eye. It is a macrocrystalline quartz, (along with rose quartz, amethyst, etc) It can be translucent to opaque and contains cat’s eyes chatoyant stripes. Chatoyancy means that the stone shows a band or bands of bright lustre caused by reflection from inclusions in the stone. The bands in tiger’s eye are caused by asbestos fibres in the stone. The stone is usually gold or a gold brown. The two cameos below illustrate the light gold banding in the stones.
The next stone is jasper. Jasper is a microcrystalline and is sometimes listed as a chalcedony and sometimes as forming a separate category of quartz. It is an opaque stone and different varieties are named due to the specific colour, like red jasper. Jasper was used a lot by the ancient Greeks and Romans for intaglios, for micromosaics in the 18th and 19th centuries and in Scottish pebble jewellery in the 19th century.
The final quartz stone is bloodstone and it falls into the plasma family comprising opaque green to dark green stones. Some include bloodstone as a chalcedony, others classify it as a jasper. Bloodstone (also known as heliotrope) is green with red spots or streaks. It was also used in antiquity for intaglios and this use continued for centuries.
This is the last post about the fabulous quartz family. I have covered most of the quartz family over the last few weeks and hopefully shown it is a fascinating family of gemstones.