Opal is the birthstone for October. Opal is probably the most famous phenomenal stone displaying the unparalleled play-of-colour; a rainbow-coloured kaleidoscopic effect. Some type of opals lack the play-of-colour phenomenon and they are known as“common opal” or “potch opal”. They contain 20% water so they can dry out easily and crack if not well looked after, Browse a few choice items here but visit us in-store to see our full collection of opal jewellery.