Tourmaline is a boron-silicate mineral occurring in a number of crystalline varieties (schorl, dravite) in igneous rocks. Crystal system is trigonal, crystal habitat is acicular, elongate prismatic crystals. Well known and much sought after for jewellery are the clear crystalline varieties that occur in different colours. The blueish green, acicular tourmaline crystal of this sample is intergrown with a double ended crystal of quartz, of which the golden-brown upper half is of the 'smokey' variety. Actual height of sample is 140 mm.