Gem Price Index

Change since 2019. Each figure compares today’s price per carat with 2019, for the same quality of stone: +50% means it now sells for 50% more per carat than in 2019; −10% means 10% less. On the chart, 100 is the 2019 price (150 = +50%).

Sources. Prices paid in live and online auctions at 4 auction houses: Christie’s (2019–2026, 1,636 stones), Sotheby’s (2019–2026, 1,140 stones), Phillips (2021–2026, 287 stones) and Bonhams (2019–2026, 333 stones), buyer’s premium included, in US dollars at the rate of the sale day. Bonhams lots are read from their full catalogue text (weight, laboratory report, origin, treatment), not from the title alone. Sales from January 2019 to November 2026; latest sale read 10 November 2026. Page updated 11 November 2026.

How. Each index follows the price per carat of the same kind of stone, quality for quality, as art and luxury indices do: every sale is set against what the stone is (weight, treatment, colour, laboratory reports, house, city, signed jewel or not), and what is left, season after season, is the market’s own movement. For rubies, sapphires and emeralds, origin drives the price, so each origin has its own line. Rubies and sapphires are unheated only (sapphires: blue); emeralds have no, insignificant or minor oil. A season with too few stones sold (under 8, more for a stone whose prices vary widely) is joined to its neighbour and drawn hollow, or the line goes to one point a year.

Every stone in the base. The board and the line under it list every stone and origin in the Precious Trade price base. A line has an index once at least 60 stones within its scope (for rubies, say, unheated rubies of that origin) have sold since 2019. The others are named in the line under the board, with the number of stones of that stone and origin sold since 2019, all qualities, and get a line once there are enough. Padparadscha: the lot is sold as padparadscha. Origin not stated: no origin in the report, or the laboratories disagree. Jadeite, sold by the piece, has an index under review: its first reading mixes very different pieces.

12 months. The last 12 months (to November 2026, the latest sale) against the 12 months before, quality for quality: the same model as the line, its periods being these two 12-month spans. Shown only when both spans have enough stones (at least 8, more for a stone whose prices vary widely).

Inflation. Figures are not adjusted for inflation. For reference, US consumer prices (CPI-U, Bureau of Labor Statistics) rose about 32% between 2019 (annual average) and September 2026.

Checked against real resales. Of 98 stones sold twice, 62 moved in the same direction as the index (repeat-sales check, the method of the Sotheby’s Mei Moses art index). The stones are listed on the Stones page.

Which stones. Only stones with a stated weight and a laboratory report. Live and online sales; online sales are controlled for in the calculation. Only a lot with one main stone, weighed and named in the catalogue (a ring, a pendant, a brooch or a loose stone), enters a line: never an accent stone, never a necklace or a jewel of several stones sold by total weight. For rubies, sapphires and emeralds the main stone must weigh at least 1 carat.

Unsold. Under the chart: of the stones offered within the line’s scope (same stone, origin, quality and weight rules), the share bought in or withdrawn, per year.

Past results, not a forecast.