Not all hydrophane opals need treatment to bring out their beauty. "Precious opal (Shewa Province, Ethiopia) 9," photo by James St. John. Licensed under CC By 2.0.

Article: Opal Treatments: How to Detect Treated Opals

Credit: James St. John

Gemstone	Opal Stone
Natural or man made	Natural
Origin	Ethiopia
Origin details	Shewa Province
Gem State	Rough
Color	White
Transparency	Translucent
Photo phenomena	Play of Color