• Gilson synthetic opals

    Opal Stone

    Gilson synthetic opals. Photo © Joel E. Arem, PhD, FGA. Used with permission.

    Article: Appraising Opals

    Credit: Joel E. Arem, PhD, FGA

    GemstoneOpal Stone
    Natural or man madeLab-made
    Origin detailsGilson synthetic
    Gem StateCabochon
    ColorRedWhite, Black,
    TransparencyOpaque
    Photo phenomenaPlay of Color