Opal Round Cabochons, AA-Grade

This natural round opal cabochon is an appealing option for custom jewelry and one-of-a-kind pieces. To bring out the opal's signature flashing colors, it is recommended that you set the gemstone over a black or dark-colored layer, or that you heavily oxidize your metal. Opal is the birthstone for October. Opal is a relatively soft mineral that comprises silicon and water and is characterized by and valued for its display of flashing rainbow colors, referred to as the "play-of-color." There are many different varieties, with gemstone colors ranging from white or light gray to brown or red to black. While opal may be found in either sedimentary deposits or in volcanic deposits; the volcanic gemstones tend to be brittle and more fragile than the sedimentary gems.

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Gemstone type: Opal
Stone shape: Round
Stone size: 5mm, 6mm, 4mm, 3mm
Stone type: Natural
Color: Blue/Green
Birthstone: October
Enhancement: None (N)
Grade: AA
Mohs hardness: 5.5–6.5
Refractive index: 1.37–1.52
Specific gravity: 1.98–2.25
Brand: AGTA
Mineral source: AUSTRALIA
Cutting center: Thailand