Vintage Cambridge Glass Azurite Blue Compote BowlOpaline is a semi opaque glass originating in France from 1810 1890 that features a milky or crystalline look with a beautiful turquoise to cerulean blue. This beautiful cerulean blue example has hints of translucency when held to the light and an applied 22k gold rim. The translucency is created by adding opacity agents like bone ash or metal oxides to the glass mixture during the manufacturing process. Blue opaline is highly prized and collected.