Chrysoprase (SiO2) is a non-transparent silica mineral. It is the most expensive type of chalcedony. The name for this mineral is derived from an amalgamation of two Ancient Greek words, ‘chrys’ meaning gold or yellow and ‘prase’ meaning green in reference to its fresh golden green colour.
Chrysoprase’s striking apple green or mint colour is caused by traces of nickel compounds. With its verdant green colour, chrysoprase is an appropriate birthstone for May and June. In medieval folklore, chrysoprase was believed to hold healing powers, particularly for treating depression and lifting the spirits. In Physica, the 12th century Abbess, Hildegard von Bingen, recommended placing a piece of chrysoprase at the base of the throat to calm anger. The 14th century Lapidaire, Chevalier Jean de Mandeville described chrysoprase power to “give graces to he who wears it and it is good for the eyes”.
There are many sources across the globe in which chrysoprase is found, from Australia, Indonesia, Russia, Poland and Brazil to Arizona and California in the United States of America. The most prominent source is in Haneti, Tanzania. The mine by Lyobo Mountain in central Tanzania has operated constantly since 1986.
Chrysoprase is fairly hardy, having a rating of 7 out of 10 on the Mohs hardness scale. It has a hexagonal crystal structure. When polished, chrysoprase has a distinctive waxy or silky appearance which casts off a soft green ‘glow’. Being opaque, rather than transparent, chrysoprase is typically polished into smooth beads or cut into cabochons that are set in jewellery. In recent years chrysoprase has been embraced by contemporary designers. Louis Vuitton’s fine jewellery collection ‘Acte V’, featured a lavish diamond necklace ending in two large chrysoprase pear drops. Piaget is another brand that has recently enjoyed the vivid colour of chrysoprase. in their ‘Extremely Piaget’ (2014) collection of fine jewellery inspired by 1970s statement style Piaget placed large chrysoprase beads alongside diamonds and turquoise.