Blue hues – Arthur Thomas
Agate blue lace
Viable deposits of this attractive agate with its delicate lacy blue and white banding occur in both South West and East Africa.
This name, derived from the Greek for “I am misleading” is probably a reference to its marked resemblance to the harder and more valuable mineral, beryl. Sapphire blue apatite is sometimes given the varietal name Moroxite it was produced as a by-product of emerald mining at the Cobra Mine, Phalaborwa. There are mines in Madagascar that produce apatite in a wide range of hues including the very collectible electric-blue and neon-green varieties.
This sea green to sky blue variety of beryl is coloured by traces of iron. It occurs in the form of relatively large, bright hexagonal crystals in pegmatite vugs. The most typical inclusions are masses of parallel negative crystal cavities termed “rain”. It is frequently associated with quartz, topaz and tourmaline. Major sources include Afghanistan, Brazil, Madagascar, Mozambique, Namibia, Nigeria, Zambia and Zimbabwe.
A copper carbonate, azurite exhibits a fabulous colour however over time it eventually alters to the more stable green carbonate, malachite. The Copperbelt of Zambia and Zaire is the principal modern source of these minerals. The famous deposits of Russia and Namibia are mostly worked out.
Combining both the blue and green carbonates azurmalachite forms beautiful specimens. It also takes a good polish so it can be cut into very attractive cabochons.
This is an exceptionally rare gem often described as having the colour of a sapphire and the fire of a diamond. Since its discovery in 1907 benitoite mining has been confined to a few very small deposits in the New Idria district of San Benito County, California. Current availability is limited to such very small fragments that can be obtained by working through the old mine dumps.
This ethereal blue gem is found in crystal lined vugs. It is relatively soft so it is generally sold as a specimen.
This translucent blue material makes wonderful sculptures but it is usually to be seen in the form of cabochons.
Compact, intensly silicified chrysocolla, termed “gem silica” is highly prized and yields popular very colourful cabochons.
Intense blues are amongst the rarest of diamonds. The best known being the Hope Diamond currently displayed in the Smithsonian Museum. It is reputed to bring ill-fortune to its owner.
This R.A.F blue material that is usually marketed as dumortierite is actually massive quartz heavily impregnated with fine needles of the blue mineral dumortierite. It is suitable for carving or cabs.
This ornamental material is Israel’s national stone. It is also called King Solomon’s stone since it was first discovered at King Solomon’s copper mines near the city of Eilat. It comprises an intergrowth of chrysocolla, turquoise and malachite.