Opal Brightness
This Opal Brightness chart shows the Opal Brightness Rating, starting from 1 out of 5 (Dull), up to 5 out of 5 (Brilliant) The rating of brightness of an Opal starts as Dull (1/5) Sub-Dued (2/5) Bright (3/5) Very Bright (4/5) to Brilliant (5/5)
Opal Body Tone – What is Body Tone?
The Opal Body-Tone Chart displays N-1 (Black) through to N-9 (White) The Body-Tone of an Opal is the variable shades of the back of the Opal, ranging from the very blackest of Black (N-1), through to the lightest body-tone of White (N-9)
Solid Opals, Doublets and Triplets How can I tell the difference?
Solid Opals: are a single (1 Piece) Solid Opal
Doublets: are made up of 2 peices: 1 piece of Sliced Crystal Opal, and 1 Piece of Black Potch (Or Black Glass) glued together.
Triplets: are made up of 3 Pieces: 1 Piece of clear quartz, 1 Piece of thinly-sliced crystal Opal and 1 piece of Black Potch All Glued Together.
Where are Opals found in Australia?
Opals are found in Australia within the entire area of the Great Artesian Basin. The area of the Artesian Basin outlines the vast In-land Sea that once covered a large part of Australia some 110 Million years ago.
How Are Opals Formed?
Opal is a hydrated amorphous form of silica and has a water content of up to 21%. The formation starts as water finds its way down through cracks and voids in the Earth. Along the way the water collects silica from sandstone and finds natural faults as its pathway down into voids, decomposing fossils and plant matter. (This is usually the clay/Opal level beneath the Sandstone) The water eventually evaporates, leaving a silica deposit behind and untimately, the formation of Opal.
What Makes an Opal Shine?
The internal structure of a precious Opal makes it diffract light. Precious Opal is composed of Silica Spheres, these Spheres produce the internal coloursby causing the interferience and diffraction of light passing through the micro-structure of the Opal. Depending on the conditions in which it is formed, an Opal can display many colours of the Colour Spectrum. ..But because of the hues in which the Black Opal displays, makes the Black Opal the rarest Opal in the world, and therefore, the most Valuable!
