Carat Weight of a Cabochon Sapphire

The Carat Weight of a Cabochon Sapphire gem calculator computes the carat weight based on the specific gravity of opal and its dimensions including a cabochon factor.   

INSTRUCTIONS: Choose units and enter the following:

• (L) length of Gem
• (W) width of Gem
• (D) depth of Gem
• (CPF) Cabochon Profile Factor              Cabochon Profile Factor Table 
• (B) Percent bulge 

Cabochon Sapphire Weight (Wt): The calculator returns the weight in carats.   However, this can be automatically converted to compatible units via the pull-down menu.

The Math / Science

The formula for the carat weight of a sapphire cabochon is:

   weight = len * wid * dep * sg * CPF * bul

where:

• weight = carat weight of a sapphire
• len = length of the gem
• wid = width of the gem
• dep = depth of the gem
• sg = specific gravity of the gem
• CPF = Cabochon Profile Factor
• bul = bulge factor 

The formula approximates the volume of the gem.  The specific gravity is used with the volume estimate to estimate the carat weight.

Cabochon Gem Weight Calculators

• Carat Weight of a Cabochon Adventurine Quartz
• Carat Weight of a Cabochon Chalcedony
• Carat Weight of a Cabochon Emerald
• Carat Weight of a Cabochon Jadeite
• Carat Weight of a Cabochon Nephrite Jade
• Carat Weight of a Cabochon Opal
• Carat Weight of a Cabochon Ruby
• Carat Weight of a Cabochon Sapphire
• Carat Weight of a Cabochon Tigers Eye
• Carat Weight of a Cabochon Cats Eye

Gemstone Carat Weight Calculator:

• Weight Estimate of a Round Faceted Gem
• Weight Estimate of a Pear shaped or Teardrop Gem
• Weight Estimate of a Cabochon Cut Gem
• Weight Estimate of a Cushion Faceted Gem
• Weight Estimate of a Heart Shaped Gem
• Weight Estimate of an Emerald Cut Faceted Gem
• Weight Estimate of a Navette Cut Gem
• Weight Estimate of Long Rectangular Cut Gem
• Weight Estimate of Square Cut Faceted Gem
• Weight Estimate of Marquise Faceted Gem
• Weight Estimate of an Oval Faceted Gem
• Weight Estimate of Lozenge Faceted Cut Gem

Types of Gems

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

ACCURACY COMPARISON

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.