PRELOVED OVAL BRASS CHROME CHALCEDONY SET MUSHROOM BROOCH

An interesting piece; a brass brooch, I would guess at mid-20th-century (but can't swear to it, hence listing as preloved rather than vintage) Chrome Chalcedony brooch.  The centre stone has little etched brass mushrooms or toadstools radiating outwards from it - a charming touch evoking nature and woodland.

The brooch measures approx. 41 x 33 mm. The oval cabochon stone measures approx. 25 x 18 mm. The brooch is in good condition with wear and tarnish consistent with its age and prior use. The weight on my scales is 14.53 grams. The pin has been added and is a simple steel pin glued on.

It has been suggested that Chalcedony was one of the earliest materials used by man. In the 7th century BC, it was used to make cylindrical seals in the area of Mesopotamia.  In particular it is used to carve attractive cameos, and is one of the gemstones used in commesso; a technique of fashioning pictures with thin, cut-to-shape pieces of brightly coloured gemstones (extremely popular in the 16th century in Florence, Italy an important city during the Renaissance). Chalcedony is best thought of as a species name, rather than a gem name. For example; Blue Chalcedony is a greyish blue coloured gem, Pink Chalcedony is more of a milky Rose Quartz colour than that seen in a vibrant pink Sapphire and Green Chalcedony is a light pastel colour.  This bewitching stone is thought to drive out dread, hysterics, melancholy, mental illness, and to reduce fever and prevent depression. The gem is mined in various parts of the world including Brazil, Madagascar and Sri Lanka and is normally located in volcanic and sedimentary rocks.

Chrome Chalcedony is the darker green variety of the mineral chalcedony, coloured by small quantities of chromium. Chrome Chalcedony is similar in appearance to the better-known Chrysoprase, but differs in that whilst Chrome Chalcedony is coloured by chromium (as chromium(III) oxide), Chrysoprase is coloured by nickel. Chrome Chalcedony (unlike Chrysoprase) may also contain tiny black specks of chromite. This is a cryptocrystalline form of silica, consisting of fine intergrowths of the minerals quartz and moganite.  It has been discovered in Zimbabwe, Western Australia, the Balkans, Bolivia, Turkey and the Ural mountains.

Chrome Chalcedony was widely used in jewellery and seals throughout the Roman Empire. The source of the mineral is unclear, as whilst Pliny the Elder described it as coming from India, no deposits have been found there. Chrome Chalcedony disappeared from use sometime in the 2nd century. It was only rediscovered when the Zimbabwean deposits were found in the 1950s.