General: This bracelet is made in Sterling Silver, and is set with two Boulder Opals.
Material: Sterling Silver.
Gem: Boulder Opal.
Mechanics: The legs are sprung and so the frog clamps itself onto the arm.
Designer: W.van Heeckeren.
Craftsman: W.van Heeckeren.
Availability: On special order only.
Price: AUS $ 4500.00
some variation may be required depending on availability and
quality of suitable Opals.
When looking at the prices, please remember that the price was when
the article was made for the Customer, and so if you would like to
have a frog Bracelet, then the design will be different, and the
price will reflect current values.
STERLING SILVER is a binary Silver alloy consisting of:
925 parts/1000 Pure Silver and
75 parts/1000 Pure Copper.
Annealing temperature: 750 degrees Celsius.
Melting Temperature: 950 degrees Celsius.
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
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
absorption spectrum: Fire opal: 7000-6400, 5900-4000
fluorescence: White:white, bluish, brownish, greenish. Black:usually none
Fire:greenish to brown