Dimensions to Carat Weight Formula

Round faceted stones:
Diameter squared x depth x S.G. x .0018 = ct

Oval faceted stones:
Length x width x depth x S.G. x .0020 = ct

Emerald cut faceted stones:
Length x width x depth x S.G. x .0025 = ct

Rectangular step cut stones:
Length x width x depth x S.G. x .0025 = ct

Rectangular scissor cut faceted stones:
Length x width x depth x S.G. x .0026 = ct

Square step cut stones:
Diameter squared x depth x S.G. x .0023 = ct

Marquise cut stones, (navette):
Length x width x depth x S.G. x .0016 = ct

Pear cut stones:
Length x width x depth x S.G. x .0018 = ct

Square cushions:
Diameter squared x depth x S.G. x .0018 = ct

Rectangular Cushions:
Diameter squared x depth x S.G. x .0022 = ct

Cabochon cut stones:
Length x width x depth x S.G. x .0027 = ct