Sardonyx Earring

Onyx which is reddish brown and white is known as sardonyx. Sardonyx was highly valued in Rome, especially for seals, because it was said never to stick to the wax. The Roman general Publius Cornelius Scipio was known for wearing it a good deal.

Onyx bracelet

In jewellery design as in fashion, colours look crisper against a background of black, and black and white always looks right. In fine jewellery, the black backdrop is often supplied by onyx, a black chalcedony quartz with a fine texture. Some onyx also displays white bands or ribbons against a black background. If the layers are even, this type of onyx can be carved into cameos.

Onyx was very popular with the ancient Greeks and Romans. The name comes from the Greek word ‘onyx’, which means nail or claw. The story is that one day the frisky Cupid cut the divine fingernails of Venus with an arrowhead while she was sleeping. He left the clippings scattered on the sand and the fates turned them into stone so that no part of the heavenly body would ever perish.

True, black isn’t normally the color one associates with fingernails. But in Greek times, almost all the colors of chalcedony from fingernail white to dark brown and black were called onyx. Later, the Romans narrowed the term to refer to black and dark brown colours only.

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  Garnet Rings

  Alaska

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Semi Precious Stone Garnet

Garnet is the name of a group of silicate minerals with the general formula A3B2(SiO4)3, the six common garnets being almandine (Fe,Al), grossular (Ca,Al), pyrope (Mg,Al), spessartine (Mn,Al), andradite (Ca,Fe), and uvarovite (Ca,Cr). All garnets are hard (6.5-7.5 on the Mohs scale), resistant to physical abrasion and chemical attack, and have relatively high melting points. Some varieties are used as semi-precious stones, but the principal commercial use is as an abrasive in sandblasting, abrasive wheels, sandpaper, and polishing grits and powders. The relatively high SG of 3.7–4.2 makes garnet a useful medium for water filtration. The preferred commercial variety is almandine although andradite is also used.

World consumption is believed to exceed 200 000 t/year. Australia produces over 70 000 t/year from a large beach sand deposit near Geraldton, Western Australia.

South Australia has had no significant garnet production even though it is a common accessory mineral in metamorphic rocks throughout the State, particularly in Cambrian Kanmantoo Group metasediments of the eastern Mount Lofty Ranges. Occurrences of almandine have been investigated in shear zones within Willyama Supergroup metasediments near Mutooroo homestead in the Olary Province. It is found in uneconomic concentrations in some mineral sand deposits, including sediments along the western coast of Lake Alexandrina which have been a recent exploration target.