Table of Contents
Tourmaline Consumer Information
As provided and validated by various gemmological organizations, laboratories and the "World Jewelry Confederation CIBJO
Rubellite – pink to red range, may also be brownish, orangy, or purplish
Verdelite – yellow green to bluish green
Indicolite – violetish to greenish blue
Dravite – yellow to brown tourmalines. One bright yellow variety has been called “canary tourmaline” in the trade
Paraiba tourmaline – eclectic, radiant, blue
Different varieties of tourmaline tend to have different clarities. Thus while large clean tourmalines in the blue and blue-green colors are available, almost all red and pink tourmalines will show eye-visible inclusions
The most common inclusions in tourmaline are fractures and liquid-filled healed fractures. Needle inclusions are also common
Tourmalines’ elongated, prismatic crystals dictate how the gemstones are cut, often resulting in very long, rectangular shapes. While tourmalines can be cut in all shapes and sizes, rectangular shapes predominate. Crystals often exhibit more than one colour; in such cases bi-colour or parti-colour gemstones result. On rare occasions, tourmalines are also carved.
Heating: This treatment aims to produce lighter green gems and blue green colours from overly dark gems. In cuprian elbaites (paraiba tourmalines), heating causes some dark purple material to become strongly greenish blue or deep blue. There are some undesirable effects of heating: some pink and red tourmaline may fade to nearly colourless upon heating
Irradiation: This treatment was used to produce darker red gems from light pinks.
Tourmalines should only be cleaned with a soft damp cloth or a soft bristle toothbrush
Paraiba tourmalines, particularly those from Paraiba, Brazil
Copper bearing gems from Mozambique and Nigeria: recent production has lagged at these sources
Strong color tourmalines from limited, high quality pockets
Bi-color and cat’s eye tourmalines
Tourmaline References in Antique Gemological Books
General Tourmaline Overviews
Streeter: Tourmaline Locations and Value
Wodiska: 10 Pages on Tourmalines
Feuchtwanger: Tourmalines (also origin of colors)
Rocks and minerals: dealer listings
Electric Stones: Scientific studies of Tourmaline’s electrical properties.
Catelle: “Tourmaline and other gemstones”
USA Tourmaline (Maine, California, NY City)
Maine Tourmaline Mining
Bastin’s “Pegmatites in Maine“.A complete book on Maine’s Tourmalines !!
George Frederick Kunz on Maine Tourmaline
Kunz report in USGS 1908 on “Maine Tourmaline”
Another USGS 1913 report on “Tourmaline in Maine”
On the discovery of “Maine Tourmaline”
Descriptions of Several top piece of Mineral Specimens
USGS 1916 Description of pink and green Tourmaline pockets.
USGS 1906 King mine Pink and Green Tourmaline production overview.
USGS 1912: Description of purchase Morgan/American Museum Pink Tourmaline pieces at end of chapter
European localities of “Black Tourmaline”
More USA Tourmaline Localities
Exceptional New York Blue Tourmaline (Indicolite)
Black Tourmaline (Schorl)
Manhattan Island Black Tourmaline unique specimens
Himalaya Mine and “Black Tourmaline”
Barrus Place, Goshen, Black Tourmaline Leiperville,
Delaware County top quality “Black Tourmaline”