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