EDUCATION - GEMSTONES
Tanzanite

Tanzanite is an extraordinary gemstone. It occurs in only one place worldwide. It is named after the East African state of Tanzania, the only place in the world where it has been found. Africa? It is a continent which provides the world with a multitude of truly magnificent gemstones, like tanzanite for example.

On its discovery in 1967, it was enthusiastically celebrated by the specialists as the 'gemstone of the 20th century'. They held their breath in excitement as they caught sight of the first deep-blue crystals which had been found in the Merelani Hills near Arusha in the north of Tanzania. Millions of years ago, metamorphic schists, gneisses and quartzites formed impressive, flattopped inselbergs on a vast plain in the shadow of Kilimanjaro.

The precious crystals grew in deposits on the inside of these unusual elevations. For a long, long time they were hidden from the eye of Man, until one day some passing Masai shepherds noticed some sparkling crystals lying in the sun and took them along with them. In Merelani today, the search is carried on for the coveted crystals in several, smallish mines, in some cases using modern methods. As a rule, only small grains are found, but now and again the mineworkers succeed in fetching out a larger crystal – to the joy of the mine owners and that of the large number of tanzanite fans.

Information supplied by the International Coloured Gemstone Association.

Gemstone Care Chart
Alexandrite
Generally stable to light, heat & chemicals. Do not boil. Ultrasonic with care (jewellers only).
  Jade
(Jadeite & Nephrite) Often polished with wax finish. Other- wise, very tough. Avoid high heat, solvents, acids & strong light. Soak briefly in ammonia, brush & Rinse.
         
Amber
Easily damaged by heat, pressure, and chemicals. Wipe or soak in soapy water. Do not ultrasonic.
  Kunzite
(Spodumene)
Do not boil or ultrasonic. Heat & strong light can change color. Soak in ammonia, rinse & brush. Avoid hydrofluoric acid.
         
Amethyst
Avoid strong heat & abrupt temperature changes. Boiling & ultrasonic should be done with care not to "shock" stone. Soak in ammonia & brush.
  Lapis Lazuli
Do not boil or ultrasonic. Often dyed. Avoid heat, solvents, acids, strong detergents. Clean gently with soapy water.
         
Andalusite
Ultrasonic OK. Do not boil.
  Malachite
Do not boil or ultrasonic. Avoid heat, solvents, acids. Clean gently with soapy water.
         
  Apatite
Heat & strong light can cause color to change or fade. Do not boil.
    Opal
Very delicate & heat sensitive. Do not boil or ultrasonic. Avoid all solvents, acids, heat, abrasion. Brush with soapy water; brush accent gems.
         
  Aquamarine (Beryl)
Ultrasonic with caution: jewellers should check for inclusions. Acids can cause damage, especially hydrofluoric. Soak in ammonia, brush. Brush accent gems & Rinse with warm, soapy water.
    Pearls
Organic; avoid chemicals, hair spray, perfume, perspiration. Very soft. Do not boil or ultrasonic. Wipe with soft, damp cloth after wearing. Do not store in dark place. Needs light.
         
  Beryl
Ultrasonic with caution: jewellers should check for inclusions. Acids can cause damage, especially hydrofluoric. Soak in ammonia, brush. Brush accent gems & Rinse with warm, soapy water.
    Peridot
May fracture if heat-shocked. Do not ultrasonic. Boil with care. Damaged by acids. Soak in ammonia & brush clean.
         
  Cat’s Eye (Chrysoberyl)
Generally stable. Avoid boiling and ultrasonic.
    Quartz
Avoid strong heat & abrupt temperature changes. Boiling & ultrasonic should be done with care not to "shock" stone. Soak in ammonia & brush.
         
  Citrine (Quartz)
Strong heat (jewellers torch) may destroy color. Boiling and ultrasonic cleaning best done carefully, by jeweller. Soak in ammonia, brush, Rinse.
    Ruby & Sapphire (Corundum)
Boiling and ultrasonic generally safe. Soak in ammonia & brush. Rinse with hot, soapy water. May have glass-filled cavities that could be dislodged.
         
  Coral
Organic material, soft & often dyed. Do not boil, ultrasonic or use chemicals. Clean with soapy water. Brush accent stones & clean with Rinse.
    Spinel
Boiling OK; avoid heat shock. Sonic cleaning OK; ultrasonic with care. Jewellers’ torch may fade light colors. Soak, brush & Rinse.
         
  Diamond
Untreated diamonds OK to boil & ultra- sonic. Soak in ammonia, brush & Rinse. Fracture-filled diamonds must be treated with care. Jeweller’s torch can remove fillings—let him know if you know your diamond is filled!
    Tanzanite (Zoisite)
Do not boil or ultrasonic. Will fracture if shocked. Damaged by hydrofluoric & hydrochloric acids. Soak in ammonia & brush, Rinse accent stones.
         
  Diopside
Do not boil or ultrasonic; do not expose to hydrofluoric acid. Very heat-sensitive. Soak in ammonia, brush.
    Topaz
Do not boil or ultrasonic. Fractures if shocked. Soak in ammonia & brush; clean accent stones with Rinse.
         
  Emerald (Beryl)
Use extreme care. Usually filled with oil or resins that might be removed with cleaning. (Fillings can be restored.) Do not boil or ultrasonic. Rinse, brush & Rinse with warm, soapy water.
    Turquoise
Do not boil or ultrasonic. Attacked by acids. Cosmetics or perspiration may discolor stone. Many are dyed or "stabilized" with resins. Brush with ammonia, rinse & dry.
         
  Garnet
Gentle boiling OK if temperature "shock" avoided. Ultrasonic with care. Sonic OK. Jewelers- avoid hydrofluoric acid & torch. Soak in ammonia, brush.
    Zircon
Do not boil; ultrasonic OK. High heat or strong light could change color. Easily abraded—handle with care. Soak in ammonia, brush & Rinse.
         
  Iolite
Gentle boiling & ultrasonic OK. Avoid thermal shock. Acids can damage. Soak in ammonia, brush, Rinse.