Point
Point
The hundredth-of-a-carat unit that has shaped diamond pricing language since the early twentieth century
The point is the unit of gemstone weight equal to one hundredth of a metric carat (0.01 ct, or 2 milligrams). The unit is principally used in the diamond trade for small stones, where the carat itself is too coarse a unit for practical communication. A 0.25-carat diamond is described as 25 points; a 0.50-carat stone as a half-pointer or as 50 points; a 0.07-carat melee as 7 pointer. The unit reflects the fine weight resolution of small-stone work and the trade's habit of speaking in whole numbers where possible.
Origin and adoption
The point as a hundredth-carat unit dates to the metric standardisation of the carat at 200 milligrams in 1907, established by the International Committee for Weights and Measures and adopted across the major trading centres in the years that followed. Before 1907, the various national carats — the Mumbai carat, the Amsterdam carat, the London carat — had differed slightly, and the metric carat brought uniformity to international trade. The point as a decimal subdivision followed naturally from the metric base.
Adoption in the diamond trade was rapid because small-stone melee pricing depends on tight weight resolution. The price differential between a 0.05-carat and a 0.10-carat stone, on a per-carat basis, can be substantial, and the point unit lets dealers communicate weight-band differences without forcing decimal arithmetic. Trade speech still uses pointer terminology: a 30-pointer, a 70-pointer, a 90-pointer, with the implication of the carat fraction immediate to a dealer's ear.
Use in diamond grading
GIA, IGI, and the other diamond laboratories report weight to two decimal places of a carat (0.01 ct, one point of resolution), with the third decimal place understood as truncated rather than rounded. A stone of 0.998 carats is reported at 0.99 carats — never rounded up to 1.00 — to prevent the practical and pricing distinction between sub-carat and carat-or-larger from being blurred. The convention is conservative: it errs on the side of understating weight rather than overstating it, and it is one of the small disciplines that contributes to laboratory credibility.
Coloured stones and the point
The point is much less common in coloured-stone trade, where weights are typically stated in carat decimals (1.27 ct, 4.53 ct) without conversion to point form. The reason is partly historical — the diamond trade developed point speech early, and other coloured-stone segments did not — and partly practical, since coloured-stone weights span a wider range and the point unit is most useful in the very small stones where diamond melee is concentrated. Coloured-stone melee for pavé work is sometimes described in points, but the convention is loose.
In the trade
For Skyjems and other trade buyers, fluency in point speech is part of the working language of the diamond business, particularly for melee, side-stone, and accent goods. A buyer asked for 30-pointer rounds knows immediately what is required without conversion. The unit appears on grading reports as the standard hundredth-carat resolution, and weight statements should be matched to invoice and laboratory documentation in the same precision.