Stones

Sapphire is usually #9 on Mohs scale, excellent in toughness, but with large fractures/inclusions, or some treatments, can be less durable. Sources are Australia, Cambodia, China, India (Kashmir), Kenya, Madagascar, Myanmar(Burma), Nigeria, Pakistan, Rwanda, Sri Lanka, Tanzania, Thailand, United States, Vietnam. India is a famous, historic source of fine blue sapphire, and production is now …

Spinel is #8 on Mohs scale, good toughness. Sources are Cambodia, Myanmar(Burma), Sri lanka, Tanzania, Thailand. Myanmar is known for fine-quality pink and red spinels. Spinel is a good candidate for the title of “History’s Most Underappreciated Gems.” Some Ancient mines that supplied gems for royal courts, from Rome to China, produced spinels. Yet, they were …

Ruby is a #9 on Mohs scale, usually excellent in toughness, but with certain treatments or large fractures/inclusions can be less durable. Sources are Afghanistan, Kenya, Madagascar, Myanmar (Burma), Sri Lanka (Ceylon), Tanzania, Vietnam, and Thailand. Thailand is the world center for treatment and wholesale trade and mine production of rubies and has been declining since …

Alexandrite is #8.5 on Mohs scale and has excellent toughness. Sources are Brazil, East Africa, Russia, and Sri Lanka. Alexandrite is a rare chrysoberyl variety with chameleon like qualities. Its color is a lovely green in daylight or fluorescent light, but it changes to brownish or purplish red in the incandescent light from a lamp …

#7.5 to #8 on Mohs scale, poor to good toughness. Sources are Colombia, Afghanistan, Brazil, Pakistan, Russia, Zambia. Colombia is one of the largest commercial producers of emeralds. Fine Colombian emeralds are highly regarded for their excellent color. Zambia, a major commercial source, as well. Zambian emeralds tend to have good clarity. Zimbabwe, the Sandawana Valley …

Diamond scores #10 on the Mohs scale, and good is to excellent in toughness. Sources are South Africa, Australia, Brazil, Botswana, China, Canada, Ghana, Guyana, Indonesia, India, Namibia, Sierra Leon, Tanzania, Democratic Republic of the Congo, United States, Venezuela.  India was the world’s only major source until the 18th century. Then Brazil’s alluvial deposits were discovered …

#7.5 to #8 on Mohs scale, good toughness. Sources are Brazil (major source), Australia, China, Kenya, Madagascar, Mozambique, Nigeria (known for intense color under 5 carats), Pakistan, United States, and Zambia. Aquamarine’s cool blue hues are reflected in its name, which comes from the Latin for “sea water” Medieval sages prescribed water touched by aquamarine …

#7 hardness on Mohs scale, good toughness. Sources are Brazil(major source), India, Namibia, Sri Lanka, United States, Uruguay, Zambia. A closely related quartz variety called ametrine contains a striking mixture of two contrasting quartzes—purple amethyst and yellow citrine. Ametrine deposits are found in Brazil, and Bolivia. Amethyst has been the most prized member of the …

#7 to #7.5 on Mohs scale, fair to good toughness. Sources are Brazil, India, Madagascar, Pakistan, Sri Lanka, United States. Almandine is probably one of the most familiar of the closely related species that make up the garnet group. It’s a fairly common red garnet, with a color range from orange-red through red to reddish-purple. …

January Almandine/Garnet February Amethyst/Quartz March Aquamarine/Beryl April Diamond May Emerald/Beryl June Alexandrite, Pearl, Moonstone July Ruby/Corundum August Spinel, Peridot, Sardonyx September Sapphire/Corundum October Opal, Tourmaline, Rose zircon November Topaz, Citrine December Turquoise, Blue zircon, and Tanzanite