Often opal
Often on crystal opals the colour play is lively and attractive. The colour in crysta opals can be on top of the stone and/or embedded deep into the stone, creating layered vivid colour play. Black crystal opals are very rare and sought after.Ĭrystal opals are definitely one of our favourites due to their versatility. The body tone of a crystal opal can vary from white to black. They can be as clear as glass or opaque, with or without a body tone. Unline most black, dark and white opals, crystal opals are transparent. Being on the other end of the scale doesn’t mean white opal is lower quality than black opal. White opals and their body tone should be graded differently. It must be noted as well that the body tone scale as a valuation tool only applies to black and dark opals. The body tone, however, is only one factor that influences the value of a black opal.
The body tone is determined by holding the stone face up on the scale and compairing its overall body tone to the shades on the scale. Only opals that have the body tone of N1 to N4 can be called black opals.
The prices of black opals vary from approximately 100 euros to tens of thousands of euros per carat.Ī body tone scale has been developed to grade the black opals. Some limited production also comes from Mintabie and Allan’s Rise in South Australia. In general black opals are the most valuable of all opals and found almost exclusively from The dark base makes the colours on the black opal glow and really stand out. The gemstone is still entirely opal and has formed naturally as a single solid piece. opal that has play-of-colour) on a very dark grey to black potch opal. Precious Black opal consists of a layer of precious opal (i.e. In fact, an opal that is just black is worthless. However, that doesn’t mean that the stone is totally black. The base colour of black opals are, as their name suggests, black or very dark grey.