Tourmaline Value, Price, and Jewelry Information - Gem Society
Tourmalines are usually weak to inert in UV light. Pink stones: inert to very weak red to violet. Other colors, generally inert. Stones may be chalky blue to strong blue in SW (Newry, Maine). Pink gems from Brazil may be blue or lavender in SW, and gems from Tanzania (golden yellow, brown, and green stones) are strong yellow in SW.