SHOW: Rings 223
Title: Ring. General: 18K Gold Ring, set with Cooper Pedy white Opal. Material: 18K Gold. Gem: White Opal. Method: Cast, constructed. Finish: Polished. Mechanics: Claw set. Designer: W.van Heeckeren. Craftsman: W.van Heeckeren. Price: AUS $ 12000.00.
18K GOLD is a ternary Gold alloy consisting of: 750 parts/1000 Pure Gold. 125 parts/1000 Pure Silver. 125 parts/1000 Pure Copper. Annealing temperature: 750 degrees Celsius. Melting Temperature: 950 degrees Celsius. Wal.
CASTING is a method by which moulten metal is poured into a mold in order to achieve the desired shape. In the "Lost Wax" method, an accurate wax model is made. The wax model is invested (put in a chrystobalite plaster), after the investment has set, the wax is burned out in a Kiln. This leaves a negative cavity into which the moulten metal may be poured. Wal.
Claw Setting is done by making a setting from wire, which has a support for the stone, from which emanate wires, which can be bent over the stone to hold it in place. Wal.
name: OPAL (Quartz group) colour: White, gray, blue, green, orange colour of streak: White mohs hardness: 5.5-6.5 specific gravity: 1.98-2.20 cleavage: None fracture: Conchoidal, splintery, brittle crystal system: Amorphous; kidney or grape-shaped aggregates chemical composition: SiO2.nH2O hydrous silicon dioxide transparency: Transparent, opaque refractive index: 1.44-1.46 double refraction: None dispersion: None pleochroism: None absorption spectrum: Fire opal: 7000-6400, 5900-4000 fluorescence: White:white, bluish, brownish, greenish. Black:usually none Fire:greenish to brown