Ratti, Carat and Gram: Weighing Gemstones the Pakistani Way

Most gem buyers in Pakistan think in ratti. Labs, cutters and international dealers think in carats. Jewellers weighing gold think in grams and tola. All three systems describe the same stone, and the confusion between them causes more arguments at the counter than any other topic. This guide sorts it out.

The carat: the world's gem unit

The carat (ct) is fixed by international agreement. One carat is exactly 0.2 grams, so five carats make one gram. Every lab report and nearly every price list outside South Asia uses it. Carats are split into 100 points, so a 0.50 ct stone is "fifty points".

Do not mix this up with karat, the purity measure for gold. A 22K ring and a 2 ct stone use two unrelated scales.

The ratti: older than the carat

The ratti began as a seed. The bright red and black seed of the gunja plant was used for centuries across the subcontinent as a small weight for gold, silver and gems. Seeds vary, so the ratti varied too, and two versions survive in daily use.

The standard gem ratti: 0.91 ct

Gem dealers settled on a ratti of 0.91 carat, about 0.182 grams. Some call it the pakki ratti. This is the ratti we use on every product page at Real Gems, and it is the one built into our ratti converter.

The sunari ratti: about 0.61 ct

Goldsmiths kept the older, lighter ratti, often called the sunari ratti. It works out to roughly 0.61 carat, about 0.12 grams. In the goldsmith's system, 8 ratti make a masha and 12 masha make a tola.

The gap is large. A "5 ratti" stone weighed on the sunari scale is about 3.05 ct. Weighed on the gem scale it is 4.55 ct. That is a difference of 1.5 carats in a stone that sounds identical on paper.

Worked examples

Here is the arithmetic, so you can check any number you are given.

1. Ratti to carat (standard): multiply by 0.91. A 7 ratti Pukhraj is 7 × 0.91 = 6.37 ct.
2. Carat to ratti (standard): divide by 0.91. A 3.40 ct Neelam is 3.40 ÷ 0.91 = 3.74 ratti.
3. Carat to gram: multiply by 0.2. That 3.40 ct stone weighs 0.68 g.
4. Gram to carat: multiply by 5. A 1.2 g piece of Aqeeq is 6 ct, or about 6.6 ratti.
5. Sunari to standard: multiply the sunari ratti by about 0.67. An elder's advice of "9 ratti" in sunari terms is roughly 6 standard ratti.

Conversion table, 1 to 12 ratti

The sunari column is approximate, because local scales differ slightly.

Which ratti did your astrologer mean?

Many buyers arrive with a weight already in mind, often advised by an astrologer or a family elder. The tradition behind those numbers varies, and so does the ratti they had in mind. If you were told "a 6 ratti Neelam", ask which ratti. If you cannot ask, compare the carat figure on our page with both columns above and pick the stone that fits either reading comfortably.

Some traditions also prefer weights that avoid certain whole numbers. That is a matter of custom, and we leave it to you and your advisor. We simply give the weight to two decimal places in both units so nothing is hidden.

Why weight is not size

Weight tells you how heavy a stone is, not how big it looks. Different gems have different densities. A 5 ct yellow sapphire is noticeably smaller than a 5 ct citrine, because corundum is about one and a half times as dense as quartz. Light materials like opal and amber look large for their weight.

Cut matters too. A deep stone hides weight underneath, while a shallow one spreads it across the top. When size on the finger matters, read the millimetre measurements as well as the carats.

Weighing a stone yourself

A pocket scale reading to 0.01 g is fine for rough checks, but it only gives you weight to the nearest 0.05 ct. For a precise figure you need a carat scale reading to 0.01 ct. Weigh stones unset, since metal adds weight, and make sure the stone is clean and dry.

If our weight ever differs from yours by more than a tiny scale tolerance, tell us. It is a fair question and we will check it. Our how we check page explains how we weigh and record every stone, and the price list shows prices against both units.