Calculations and Formulas for Gemstones

Carat Weight.. Given the cut and dimensions of a stone, estimate its weight in Carats. Optimized on over 1,000 individual gemstones. A full 300 stones to choose from. All measurements in mm and Carats.

Stone Identification. Given the dimensions and the weight, estimate the specific gravity of your stone and guess at its identity. All measurements in mm and Carats.

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Web Award! Gimpsy is a new directory that holds only carefully reviewed interactive sites. We are very pleased to inform you that the Gimpsy editorial team has ... Thank you for your high quality site. Please accept our congratulations! (Jan 2003)

VERY VERY VERY EXTENSIVE. I had your old Calculators online for years but then for some reason it went blank - Thank YOU very much for letting me know that it is back online & Congratulations on upgrading it - it is EXCELLENT. Have a Great Week - Jim Martindale, Martindale's Reference Desk (Mar 2003)

Precious Metal Value Calculator. Evaluates the current on-line price of all carat golds, silver, platinum, and palladium. Uses the current on-line price for a variety of currencies.

Actually won two Web Awards way back in Nov 97, the Cool Central Site of the Hour and the Yahoo Incredibly Useful Site of the Day. Yahoo said: "Want to avoid getting shortchanged on great-grandma's silver? Cancel that trip over to the guy with the loupe. If you have your own scale, the Precious Metal Calculator is just as good. Fill in the weight of your gold, silver, platinum, palladium, or rhodium and the currency you would love to cash it in for, click "Calculate Value," and you get the absolute current going price for it. You can even figure out the dealer's markup. This is a deceptively simple site that provides a remarkable, incredibly useful service that would be hard to find in any other medium."

NEW! Wax Calculator for Castings. You have a wax, but need to know the weight of the cast gold piece. And its value. Or you have a brass or silver model. This page evaluates the current on-line price of all carat golds, silver, platinum, and palladium. Uses the current on-line price for a variety of currencies.

Units Calculator. Convert weights between grams, carats, pennyweights, and ounces.

General Units Calculators. Convert all sorts of units. There are several great ones on the Web, here are two.

Mass/Weight Conversions. Did you ever hear of a denarium or a duella or perhaps a zolotnik or a berkovets? ku ping or doite? Know the difference between a long hundredweight and a short hundredweight? Here is an incredibly extensive mass conversion site. All units are conserved, so you need have no worry that these are Weapons of Mass Destruction. How about a mite or a koku?

Time Around the World. Determine the current time everywhere. Accounts for Daylight Savings, 15- & 30-minute zones, etc.

The first one is not blazingly fast, but actually finds a computer on the Web in the land you indicate, and interrogates it as to its local time. I wish I'd written this one!

The second one has a neat globe display that you can turn with your mouse

The first one a List of Calculators from Jim Martindale. Do you believe 17,000 of 'em?

The second one is a list of references from the same hard-working guy. Fantastic!

This page was down for a few years, but now it is back up, better than ever! For example, Stone Identification now makes guesses at actual identity (eg, Diamond, Quartz), not just specific gravity.

Another great list: Sites That Do the Work For You