* Schorl (Jewelry) - Definition - Online Encyclopedia
The most common species of tourmaline is ~, the sodium iron (divalent) endmeer of the group. It may account for 95% or more of all tourmaline in nature. ~ Black Tourmaline. Screw Back A type of earring attachment for non-pierced ears where the earring is tightened against the earlobe by means of a screw with a flat padded end.