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Crystal opal is transparent and is pure opal (hydrated silica). It typically has sharp clarity of diffracted colour visible from within and on the surfaces of the opal. When held out of the direct light, crystal opal displays some of the most intense opal colour. This is the type of opal used in opal inlay jewellery, which has the base of the setting blackened before the precision cut crystal opal is set into it

White opal is the most common type of precious opal with a milky appearance which dominates the diffracted colours. All of the opal fields produce white opal with most of it being