The Long Rectangular Cut Gem Weight calculator computes 
the approximate carat weight of a Long Rectangular Cut Faceted colored stone (e.g. Ruby).
INSTRUCTIONS: Choose units and enter the following:
- (GEM) a choice of the type of gem
- (L) the length of the gem
- (W) the width of the gem
- (D) the depth of the gems
- (B) a pad of the weight with a percentage for any central bulge
Long Rectangular 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 long rectangular 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.