Cushion Faceted Gem Weight

The Cushion Faceted Gem Weight calculator computes the approximate carat weight of a square or rectangular Cushion Faceted gemstone (e.g. Ruby).

INSTRUCTIONS: Choose units and enter the following:

• (GEM) Choose Type of Gem
• (L) Length Down Gem Face 
• (W) Width Across Gem Face
• (D) Depth of Gem
• (B) Pad for the weight with a percent adder to compensate for any significant central bulge

Cushion Cut Gem 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 weight of a cushion cut gem is a function the volume and the specific gravity.  The volume is estimated base on the gem's shape and dimensions.  The specific gravity is dictated by the type of gem.  For the specific gravity of different gem, CLICK HERE.  

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.