Gemstones L - R
This beautiful opaque blue gemstone has been mined since antiquity, the principle ancient source being Afghanistan. It was highly prized by the Ancient Egyptians amongst others, both for decorative objects and also as a cosmetic in the form of eyeshadow. Mediaeval painters ground up lapis lazuli and used it as blue pigment ultramarine.
It is mainly composed of the mineral lazurite in conjunction with pyrite and calcite.
It can also be found in Chile, USA, Russia and Argentina and has a hardness of 5 - 5.5. It is distinguished from sodalite by its association with pyrite.
A type of feldspar, known for its irridescent colours. Gemstone quality labrodorite comes from Russia, Madagascar and Finland. It has a hardness of 6 - 6.5.
Malachite has been used since ancient times as a gemstone, pigment and cosmetic. It is a green copper carbonate hydroxide which has swirls and bands in different shades of green.
Large quantities were found in Russia in the nineteenth century, some of which was used to make the famous malachite pillars of Saint Isaacs Cathedral in Saint Petersburg. Its presence is a useful indication to prospectors of the presence of copper and it is often associated with azurite.
It can be found in Russia, USA, Morocco and Australia and has a hardness of between 3.5 - 4
A opalescent type of feldspar with a blue or white irridescent sheen. It was used by the Romans to make jewellery in ancient times.
It can be found in Myanmar, USA, Brazil and India and has a hardness of 6 - 6.5
Opal is a hardened silica gel. The flashes of colour and shimmering rainbow colours of precious opal are produced as light is split into colours by tiny spheres of silica. Most of what is found is described as potch and is dull and opaque, this can be used as a filler or an abrasive.
Until the nineteenth century, opals were only found in Slovakia, but were discovered in Australia in 1887, the Lightning Ridge field producing the rare and costly black opal. Sometimes opal can replace bone or wood during the fossilization process. It has a hardness of 5 - 6.
Rhodochrosite is nearly always pink and is generally found in hydrothermal veins. It is a soft mineral, with a hardness of only 3.5 - 4. It can be found in USA, Romania, Mexico and many other countries.
Rhodonite is a manganese silicate and often has black or darker veins of manganese oxides running through it. Its usually cut as cabochons or beads or even carved to make larger decorative objects. It can be found in many countries including Brazil, Russia, USA and Australia. It has a hardness of 6.
A pale pink variety of quartz. It has been carved since ancient times, rarely forming crystals but more often found as a massive aggregate. Large of amounts of rose quartz are found in Madagascar, but it also occurs in Brazil, Russia and USA. It has a hardness of 7.