Kunzite

Kunzite is a stone from the recently discovered gem family spodumene, which also includes the rarer hiddenite. This means that the majority of the material remains within the hands of collector’s but that doesn’t stop us from admiring this stone and wanting to utilise it in our jewellery.

This species of gemstone comes in large sizes, has a wonderful lustre, comes in gorgeous colours and, for the time being at least, is great value for money. The lilac-pink kunzite (coloured by manganese) was named after the gemologist G. F. Kunz, who first described the stone in 1902, while soft green hiddenite (coloured by chromium) was named after W. E. Hidden who discovered it in North Caroline in 1879.

The crystals are pleochroic, which means that different intensities of colour can be seen when viewed from different angles. This affects the way the stone is faceted as the table facet must lie perpendicular to the main axis of the crystal in order to secure the strongest colour possible. The clarity of gem-quality spodumene is excellent and once cut and polished the stones are full of life, possessing a vivid, almost iridescent lustre.

The word spodumene is Greek for ‘ash-coloured’ as most non-gem crystals are opaque and white to yellowish grey. It was discovered that green or bluish lilac material has a tendency to turn lilac-pink when exposed to sunlight. Because of this phenomenon, spodumene is frequently heat treated to improve or change the colour of the stone. The process of irradiation is is also used to darken pale lilac material to a strong rose-pink colour.

Sources:
Judith Crowe, The Jeweller's Directory of Gemstones (London: A&C Black, 2006)
Cally Hall, Gemstones (London: Dorling Kindersley, 1994)
Jaroslaw Bauer and Vladimir Bouska, A Guide in Colour to Precious & Semiprecious Stones (London: Octopus Books, 1983)