Tourmaline

Mineral specimens from the gem pegmatites north-east of Ramona in San Diego County, California, are hardly ever seen, certainly in Great Britain, so this large cabinet display Tourmaline crystal is a quite remarkable, striking and rare specimen, especially from the Little Three mine.  This is an ex-matrix crystal whose paragenesis (sequence of crystal development) can be seen in its base where it has been cleaved from in-situ.  The Tourmaline crystal has a 4.5 to 5 cm diameter core of semi-translucent, dark green verging on black Tourmaline surrounded by a 1 cm wide band of off-white-cream glassy Tourmaline.  The final outer skin, covering the specimen, is a transparent to semi-transparent limey-apple to bottle-green with vertical striations.  Because of the outer green layer’s transparency and the inner cream layer’s translucency, the overall appearance of the crystal is that of multiple shades of green covering a reflective metallic foil.  A quite magnificent and striking effect.  Back-lit, the crystal has a 5 mm deep gemmy intense lime-green cap which forms its near-perfectly flat pinacoidal termination.  This is a wonderful display Tourmaline from a rare Californian locality.