Tanzanite (tanganite) – gemmological name of a transparent, blue-toned variation of zoisite. Wrongly called „Mere’s sapphire” – the discoverers first mistook it for such.
The name comes from Tanzania, the land of discovery, and was introduced by Tiffany, a jewellery company from New York.
In gemmology just since 1967 Thanks to Indian gem seeker Manuel de Souz. Word has got round about the stone mainly because of Elisabeth Taylor’s jewellery.
The stone forms columnar crystals with explicit vertical striatio. It’s color may be strengthened by heating it up to 400-500 °C. May contain vanadium, strontium, chromium impurities. Fragile, some specimens exhibit chatoyancy after the cut.
Pleochroism: strong blue-green; trichroism visible to naked eye.
Possible to mistake for amethyst, cordierite, lazulite, sapphire, spinel and synthetic corundum. Immitations known.
Encountered in pegmatite-hydrothermal veins in gneisses.
Area of occurence: Tanzania – Gerevi Hills (Arusha and Moshi regions).
All kinds of jewellery,
Very rare and attractive gemstone,
COLOR: Ranges between Pinkish Red to Vivid medium-dark toned red
ORIGIN: Burma, Madagascar, Thailand, South India, SriLanka, Afghanistan, China, Tanganyika
CHEMICAL COMPOSITION: Al2O3: Cr (aluminium oxide with chromium)
SPECIFIC GRAVITY: 3.97 – 4.05
REFRACTIVE INDEX: 1.768–1.772
FORMATION: The commonly held belief amongst geologists is that rubies are formed by tectonic plates smashing together forcing limestone deposits deep into the earth where intense heat and pressure metamorphosed the limestone into sparkly marble.
UNUSUAL PROPERTIES: Ruby stone has a vibration that radiates with an intensity that projects energy and enthusiasm for life. It encourages leadership and increased concentration, with sharpness of intellect. Its energy may assist you with clear visualization, through its stimulation of the pineal gland. The 40th anniversary is considered to be significant for Ruby and is celebrated worldwide.
USAGE: Ruby is used in all forms of jewellery, including bracelets, necklaces, rings, and earrings. It is used both as centrepiece gemstone in pendants and rings, as well as a secondary stone to complement other gemstones such as Diamonds.
COLOR: There is a large range of colour for Natural Blue Sapphire from pale, greyish blue to deep pure blue, with slight violet secondary. The best range is a light to medium, fine ‘cornflower’ blue which is not too dark.
ORIGIN: Kashmir (India), Burma, Sri Lanka, Cambodia, Thailand, Vietnam
CHEMICAL COMPOSITION: Al2O3 Corundum (Aluminium Oxide)
CUT: Round Cut, Oval cut
SPECIFIC GRAVITY: 3.95-4.03
REFRACTIVE INDEX: 1.762-1.788
HARDNESS: 9(Hardest after Diamond)
FORMATION: Found usually in igneous rocks or alluvial deposits.
TREATMENT: The stones were subjected to very high temperatures: highly altered zircon inclusions, internal re-crystallization, internal diffusion around rutile crystals, synthetic overgrowth, and severely damaged crystals of unknown identity. Furthermore, the presence of color zoning that conformed to the external faceted shape of the stone suggested some level of diffusion technology. Beryllium in Be2+ form has a very small ion; it is therefore capable of penetrating deep into the sapphire, via diffusion, during heat treatment.
UNUSUAL PROPERTIES: Sapphire is the birthstone for those who are born in September. Sapphire is given as a gem for the 5th, 23rd and 45th wedding anniversaries. A real blue sapphire gemstone is one of the hardest known minerals. It can’t be scratched easily. Blue Sapphire is a very cold gem. It brings wealth, name and fame. Also gives good stamina, longevity and security in life. Can improve fertility in a barren woman. Best suited for joy, love and happiness. It cures fainting, fits, virility, mental disorder, deafness and baldness.
USAGE: Engagement Rings (highly popular), Rings, Bracelet, Exquisite Pendants or lockets, necklaces or any other jewellery.
COLOR: Emeralds are available in many shades of green. Natural Emeralds are available from medium to darker green to blue-green and sometimes slightly yellowish-green beryl. The color of the Emeralds depends on the origin of the stones.
ORIGIN: Natural Emeralds can be found in Colombia, Brazil, South Africa, Zimbabwe, Russia, Afghanistan, Australia, Ghana, India, Madagascar, Malawi, Mozambique, Namibia, Nigeria, Pakistan, Tanzania, Zambia and the United States
CHEMICAL COMPOSITION: Al2Be3Si6O18 (Aluminium beryllium silicate)
CUT: Round, Oval, Pear, Square, Emerald, Marquise, Trillion, Heart
SPECIFIC GRAVITY: 2.67-2.8
REFRACTIVE INDEX: 1.565 – 1.602
HARDNESS: 7.5 – 8
FORMATION: Emeralds are formed by hydrothermal processes associated with magma and also by metamorphism. Deposits are found in biotite schist, clay shale, in lime stones, with pegmatite. Mining is nearly from host rock, where the emerald has grown into small veins or on walls of cavities.
TREATMENT: Because emeralds are naturally full of cracks and fissures which make it more opaque and less attractive, it has become an industry standard to fill the cracks in emerald, thereby improving its clarity. Traditional fillers are natural oils such as cedar oil. Other methods of filling cracks in emerald are being explored such as waxes, resins and even glass.
UNUSUAL PROPERTIES: Emerald gemstone improves the nervous system, the decision taking becomes more mature and the person is able to give deep thought to his reactions and decisions. Thus better judgments based on deep all inclusive thinking leads to decisions that are able to turn the tide in one’s favour and give long term very strong positions.
The chief deity of India’s most famous temple, the Madurai Minakshiamman temple, is goddess Minakshi, whose idol is made of emerald, most likely carved out of a single emerald stone.
BIRTHSTONES: Emerald is regarded as the traditional birthstone for May as well as the traditional gemstone for the astrological signs of Taurus, Gemini, and sometimes Cancer.
USAGE: Rings, Earrings, nose pins, necklaces, and any other jewellery, beaded and tumbled jewellery.