Opal specimen raw milky common or boulder opal.
This is a large specimen which has some colour but not the ‘fire’ found in the precious variety.
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“Common opal” does not exhibit a “play-of-color”. It is given the name “common” because it is found in many locations throughout the world. Most specimens of common opal are also “common” in appearance and do not attract commercial attention.
However, some specimens of common opal are attractive, colorful and lustrous. They can be cut into gemstones that accept a high polish. They can be beautiful but simply lack a play-of-color that would earn them the name “precious”. Common opal is frequently cut as a gemstone and can command reasonable prices.
The origin of the name is uncertain. It may be from the Sanskrit “upala”, meaning “stone” or “precious stone” or from opalus, the ancient Latin name for the gem (Pliny the elder, 75-79). Pliny may have also referred to the gem as paederos, but a modern commentary by Kostov (2008) questions if that name was actually applied to the opal of modern sense.