Aventurine		Description Aventurine is chalcedony or microcrystalline quartz, and takes its name from the Italian words a ventura which means 'by chance', which refers to its similarity to goldstone, a man-made gemstone which was discovered by accident in Italy in the 18th century. Colours include green, brownish-green, bluish white, blue-green, grey, orange and pink. Unless a colour is specified, the name generally refers to the green form, which for jewellery is the most desirable colour. The inclusions which give Aventurine its colour become more obvious the darker the colour, giving rise to a speckled effect known as aventurescence. Green Aventurine has been mistaken for both Amazonite and Jade, but unlike them the translucent forms may fade in strong sunlight. High quality green Aventurine contains few if any inclusions and as a result it has also been called 'Indian Jade'. The Science Aventurine is chemically silicon dioxide (quartz) and owes its colours to inclusions of a variety of different minerals, mostly micas. Green Aventurine contains a chromium mica called fuschite; the pink form contains haematite; ordinary mica gives Aventurine a silvery sheen while goethite imparts a grey colour. The colour may fade if the stone is exposed to sunlight for an extended period of time. 7.0 on the Moh's Hardness Scale Care and Cleaning Soft polishing cloth, plain water rinse or mild solution of soap and water. Aventurine may also be cleaned using ultrasonics or steam. History There is little in the historical record regarding Aventurine, although it was used to improve near-sightedness, stimulate creativity and improve perception in ancient Tibet. In recent history, the Czars of Russia often gave Aventurine vases as gifts. One notable such was the gift given to Sir Roderick Murchison in thanks for the work he did in carrying out a geological survey of Russia's mineral wealth. The vase stands four feet high and has a circumference of six feet. It is made from an iron-stained micaceous Siberian Aventurine and is remarkable more for its size than its looks. Today, Aventurine is very highly prized by the Chinese, more so than Jade. It continues to be used for jewellery and carvings all over the world, and in particular is associated with St. Andrew.