What is the international unit of measurement for gem weight?

The international unit of measurement for gem weight is the metric caret. This unit specifically pertains to gemstones and pearls, where one metric caret is equivalent to 200 milligrams (0.2 grams). The use of metric carats allows for a standardized way of weighing gems across the global market, which is essential for consistency in trade, valuation, and certification within the gemological field.

While grams, pounds, and ounces are general measurements of weight, they are not used in the context of measuring gemstone weight. The metric caret is uniquely defined for this purpose, ensuring clarity and uniformity in the gem industry. This is why the metric caret is the correct choice for measuring gem weight.