The Carat Weight of an Opal Cabochon calculator estimates the carat weight based on the specific gravity of opal and its dimensions including a cabochon factor.
INSTRUCTIONS: Choose units and enter the following:
Cabochon Opal Weight (Wt): The calculator returns the weight in carats. However, this can be automatically converted to compatible units via the pull-down menu.
The formula for the carat weight of a opal cabochon is:
weight = len * wid * dep * sg * CPF * bul
where:
The formula approximates the volume of the gem. The specific gravity is used with the volume estimate to estimate the carat weight.
The gems supported in gemstone carat weight calculator include the following:
Agate, Alexandrite, Almandite garnet, Amethyst, Andalusite, Aquamarine, Aventurine, Beryl, Bloodstone, Blue Topaz, Carnelian, Cats eye, Chalcedony, Chrysoberyl, Citrine, Corundum, Demantoid Garnet, Diamond, Emerald, Golden beryl, Green beryl, Jadeite, Kunzite, Lapis Lazuli, Morganite, Nephrite Jade, Onyx, Opal, Precious topaz, Pyrope garnet, Quartz, Rhodolite garnet, Rose Quartz, Ruby, Sapphire, Sardonyx, Smokey quartz, Spessartite garnet, Spinel, Tanzanite, Topaz, Tourmaline, Tsavorite garnet, Turquoise, Yellow topaz, Zircon
The carat weight equations and data used in vCalc's jewelry library and calculator were reviewed by a certified gemologist. The equations are based on industry recognized formulas and data. The table below shows a comparison of computations between vCalc and an industry accepted application (Quantum Leap).
The length, width and depth are in millimeters (mm), and the Quantum Leap and vCalc measurements are in carats (cwt).
The largest variance, an oval faceted alexandrite, which can be seen in the last row above, has been double checked against several source equations which tend to support vCalc's accuracy.