Watch & Jewellery Glossary
A cabochon stone is flat on the underside and domed and polished on the top. This contrasts to cut gemstones. It can be in any shape although is most frequently an oval shape.
Displaying colours which seem to shine within it when seen from different angles.
Another word for Mother-of-Pearl. It is the smooth, hard surface which has formed on the inside of some mollusc shells and also on the outside surface of pearls. It is a white colour but with other colours shining within it – it is iridescent.
An opaque material that reflects light to change its colours. It has a red/yellow colour if the light is transmitted through the stone, or a bluish appearance when the light is dispersed throughout the stone perpendicular to the way the light is shining into the stone. It occurs when the stone forms in layers during crystallisation – such as what happens with moonstone and opal (in fact opalescence is named after the opal in which it occurs). If the layers are thin, a bluer appearance occurs, thicker layers reveals more of a white appearance.
A term used to describe iridescence and often used to describe Precious Opal (which does contain play-of-colour) compared to Common Opal (which doesn’t).