Black Tourmaline with Hematite and Feldspar Tower #02

263g / 0.580bs / 9.28oz 4.25" x 1.92" x 1.55" Tourmaline is a complex aluminum borosilicate with a hardness of 7 to 7.5. Its crystal pattern is hexagonal (trigonal) with prismatic crystals and striations running parallel to the main axis. No other gemstone has such wide variations in colors. Tourmalines can be red, pink, yellow, brown, black, and various shades of green, blue lilac and violet. Often the colors vary, sometimes widely, within a single specimen. Crystals with a pink center, surrounded by an outer layer of green, are called Watermelon Tourmaline. Heating and cooling or rubbing a Tourmaline crystal can cause it to become electrically charged, with one end negative and the other positive. When charged, the crystal will attract dust particles or bits of paper. This property of pyroelectricity (from heat) or piezoelectricity (from pressure or rubbing) was known to Dutch traders who used the crystals to pull ashes from their meerschaum pipes, and they called them aschentrekkers