The Carat Weight of an Opal Cabochon 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:
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.