What is tourmaline?
Tourmaline is a six-member ring cyclosilicate having a trigonal crystal system. It occurs as long, slender to thick prismatic and columnar crystals that are usually triangular in cross-section, often with curved striated faces.
Where is Tourmaline found in Africa?
In the late 1990s, copper-containing tourmaline was found in Nigeria. The material was generally paler and less saturated than the Brazilian materials, although the material generally was much less included. A more recent African discovery from Mozambique has also produced tourmaline colored by copper, similar to the Brazilian paraiba.
When was pink tourmaline first used as a gift?
Native Americans have used pink and green tourmaline as funeral gifts for centuries. The first documented case was in 1890 when Charles Russel Orcutt found pink tourmaline at what later became the Stewart Mine at Pala, California in San Diego County.
How to identify paraiba tourmaline?
Any blue tourmaline that is diamagnetic can be identified as paraiba tourmaline colored by copper in contrast to magnetic blue tourmaline colored by iron. Some tourmaline gems, especially pink to red colored stones, are altered by heat treatment to improve their color. Overly dark red stones can be lightened by careful heat treatment.
Tourmaline is a name applied to a family of related minerals with widely varying properties. Tourmalines make very popular jewelry stones and come in an amazing range of colors, including multi-color zones. Start an IGS Membership today for full access to our price guide (updated monthly).
How big is a private collection of tourmaline?
Private Collection: 258.08 (green cat’s eye); 256 (green, Maine, very large for locality). Tourmaline rough can challenge even experienced gem cutters. Multi-colored gems are often weak where the colors meet, but all color varieties may have stressed areas.
Which crystals are bi-color tourmaline?
Crystals are frequently color zoned along their length (bi-color, tri-color, parti-color, and so forth) or concentrically zoned (watermelon tourmaline). Bi-color tourmalines: Brazil (4.92, 23.90, 14.32). Photo © Joel E. Arem, PhD, FGA. Used with permission. The vast majority of cut tourmaline gemstones belong to the elbaite species.