Gemini Birthstone (Black Onyx)

Date: 21st May - 21st June

Onyx is a cryptocrystalline form of quartz. The colours of its bands range from white to almost every colour except shades such as purple and blue. Commonly specimens of onyx available contain bands of colours of white tan and brown. Pure black onyx is the most famous variety and has a long history of use for hardstone carving and jewellery.