Opal, a form of mineral silica and water, is characterised by its warm rainbow flashes when moved in the light, often referred to as play of colour. The birthstone for october, opal has generally been known to be an emotional stone, intensifying emotions, encouraging independence and stimulating creativity. This round opal cabochon measures 2mm. Opal has a hardness of 5 - 6.5 on the Mohs scale and a specific gravity of 2.15. Please note that due to the nature of the stone, each stone is unique so iridescence, colours and colour play will vary and natural inclusions may be present. Care: As with all gemstones, care must be taken. It is not advised to place opal stones in an ultrasonic, steam cleaner or chemical cleaning solution. Opal can be easily cleaned with a warm soapy water mix or an untreated cloth. It is advised to avoid exposing opal to prolonged periods of heat and light. A slight tolerance of +/- 0.25mm should be expected with these stones and these opals are sold individually. Cooksongold Opal is sourced from: Australia or China. Round Cabochon (flat backed) Natural gemstone Hardness: 5 - 6.5 on the Mohs scale Healing properties: Independence, Creativity, Healing Country of Origin: Australia or China