Rapaport Press Release: Diamond Market Cautious at Start of Year

1-carat RAPI down 2.3% in December.

LAS VEGAS--(BUSINESS WIRE)--Diamond market trends intensified in December. Polished prices above 1 carat held up; diamonds under that fell sharply. The industry entered 2026 with the same dynamics and concerns that were present for most of last year.

US dealers were mainly positive about the season and were waiting for the results of memo conversions. Retailers managed inventory carefully, resulting in last-minute orders. Demand focused on 1.20-carat and larger diamonds, especially long fancies. Synthetics continued to gain market share in fashion jewelry.

India’s export business was slow because of US tariffs. Indian domestic demand also weakened in the past month, having been one of last year’s strongest markets. Nervousness about synthetics grew as Titan Company launched lab-grown brand beYon. China’s appetite for diamonds remained low.

	RapNet Diamond Index (RAPI™)
	Index on Jan. 1, 2026	December 2025	4Q 2025	2025
RAPI 0.30 ct.	835	-9.3%	-18.5%	-20.3%
RAPI 0.50 ct.	1,244	-6.4%	-13.7%	-26.0%
RAPI 1 ct.	4,146	-2.3%	-6.5%	-9.9%
RAPI 3 ct.	18,208	0.3%	0.7%	-0.3%

The RapNet Diamond Index (RAPI™) for 1-carat goods — which tracks round, D to H, IF to VS2 diamonds — dropped 2.3% in December. The RAPI slid 9.3% for 0.30-carat diamonds and 6.4% for 0.50-carat goods, mostly reflecting declines in India. The 3-carat index increased 0.3%.

This split between large and small diamonds characterized 2025. While the 1-carat RAPI fell 9.9% for the year, the index for 0.30 carats slumped 20.3%, and 0.50-carat prices tumbled 26%. RAPI for 3-carat goods crept up 0.3%. Diamonds of 7 to 15 carats ended the year with strong demand.

SI-clarity goods, which the RAPI excludes, saw a weaker trend amid competition from synthetics. Prices for round, 1-carat, D to H, SI diamonds slid 24.1% in 2025. Smaller goods fell more sharply — mainly in the second half of the year, due to tariffs and to major retailers shifting away from natural.

The industry awaited a US-India trade deal and remained cautious about synthetics, the sale of De Beers, high gold prices, and sanctions on Russia. Current trends look set to continue, with long fancies outpacing rounds, and 1.20-carat and larger goods gaining popularity.