Q3 2026 Diamond Market Report

Executive Summary 

Q3 2026 showed a Natural diamond market moving onto firmer ground. 

After two quarters of price pressure, the broader Natural market moved higher. The Natural Diamond Index increased by 3%, with both Rounds and Fancies finishing the quarter in positive territory. The increases were not extreme, but that is what makes the quarter important. Q3 was less about a sharp rally and more about stability returning across a much wider part of the market. 

The clearest recovery came from smaller Rounds. 0.30ct and 0.50ct goods saw meaningful price increases globally and in the US, while 1ct goods finally stopped the downward trend seen throughout the first half of the year. Higher up the size curve, 2ct prices remained almost completely stable and 3ct goods continued to hold their ground. 

The US followed the same broader improvement, but tariffs played an important role in how the quarter developed. Pricing became volatile around the late-July tariff decision, before recovering through August and becoming more stable during September. Greater clarity around the cost of bringing goods into the US removed some of the uncertainty that had weighed heavily on the market earlier in the year. 

Lab-Grown followed a different path. Prices continued to decline, but at a much slower rate than in Q1 and Q2. 

The story of Q3 was therefore not that diamond prices suddenly surged. It was that the Natural market stopped moving backwards. Smaller goods began to recover, weaker categories stabilized, and the quarter finished with significantly stronger pricing support than the first half of the year.  

The Natural Market Found Firmer Ground 

The first half of 2026 was defined by pressure. 

The Natural Diamond Index decreased by 3.6% in Q1 and another 3.27% in Q2. But beneath those headline numbers, the market had already started changing. Rounds became more stable during Q2, while Fancies continued to carry most of the weakness. 

Q3 was the point where that stability broadened. 

The Natural Diamond Index increased by 3%, with Rounds up 3.5% and Fancies up 2.6%. 

The important change was not simply that the index turned positive. It was that the improvement was no longer limited to one shape group. In Q2, Rounds had stabilized while Fancies were still falling sharply. In Q3, both moved higher. 

That made Q3 the first quarter of the year where the Natural market showed broad stability rather than isolated pockets of strength. 

Tariff Clarity Helped the US Reset 

The US market had spent much of 2026 reacting to tariffs. 

In Q1, changing tariff expectations created a hesitant buying environment and US Natural prices fell considerably more than global prices. By Q2, the market had become more selective, with some US categories performing well while others remained under pressure. 

Q3 brought another important change. 

In late July, the US finalized its new tariff structure. India remained in the 10% tariff tier, while European-cut & polished Natural diamonds regained tariff-free access to the US. 

The structure was not equal across sourcing centers, but it gave traders something they had been missing for months: greater clarity around landed costs. 

That timing is visible in US pricing. 

The market saw a clear price drop toward the end of July before recovering strongly through August and becoming considerably more stable during September. 

By the end of the quarter, the US Natural Diamond Index had increased by 4.26%, with Rounds up 3.8% and Fancies up 4.8%. 

The tariff decision should not be treated as the only reason prices improved, but it removed an important source of uncertainty. Earlier in the year, traders were trying to price goods while also trying to understand what the final cost of importing them might be. By Q3, the rules had become clearer. 

The US market was still adjusting to tariffs, but it was no longer adjusting to constantly changing expectations. 

The Recovery Started at the Smaller End 

The strongest sign of recovery came from smaller Natural Rounds. 

0.30ct and 0.50ct goods recorded some of the strongest price increases of the quarter, both globally and in the US. 

The 0.30ct category was particularly interesting because the recovery happened despite a huge increase in available inventory. Global prices increased by 7.75% while supply increased significantly. In the US, prices increased by 8.4% even as supply also increased significantly. 

That is an important change from earlier in the year. More inventory did not translate into weaker pricing. The market absorbed substantially more goods while prices continued to rise. 

The 0.50ct category reached the same result through a different route. Global prices increased by 8%, while US prices rose 5.3%, but supply became tighter rather than expanding. 

Together, these categories show where the Natural recovery began. 

Earlier in the year, larger goods had been the clearest area of stability. In Q3, the strongest price movement appeared much lower down the size curve. 

Stability Spread Beyond the Smallest Goods 

The improvement did not stop at 0.30ct and 0.50ct. 

The 1ct category had been under sustained pressure throughout the first half of the year. Global prices fell 3% in Q1 and another 3.42% in Q2. In the US, the decline was even sharper in Q1 before easing during Q2. 

Q3 broke that trend. 

Global 1ct prices increased by 2%, while US prices were almost completely unchanged, increasing by 0.2%. 

The US result is particularly important because supply increased. Despite buyers having considerably more inventory available, prices did not continue falling. 

The downward trend had stopped. 

A similar change appeared in 2ct goods. 

In Q2, the US 2ct market came under meaningful pressure, with prices down 6.1% as supply increased. 

In Q3, US supply increased even more, but prices decreased by only 0.25%. 

The market absorbed significantly more inventory without repeating the price correction seen one quarter earlier. 

At the larger end, 3ct goods continued to do what they had done throughout 2026: remain stable. Global prices increased by 2.2%, while US prices rose 2.5%. 

So the Natural market was improving at different speeds. 

Smaller goods were recovering. 

1ct goods stopped falling. 

2ct goods regained balance. 

3ct goods remained resilient. 

That is what made Q3 different from the first half of the year. Stability was no longer confined to a few categories. 

Lab-Grown Kept Decreasing, But Much More Slowly 

Lab-Grown did not experience the same recovery. 

Prices continued to move lower, but the pace of decline slowed substantially. 

The Lab-Grown Diamond Index decreased by 1.3% in Q3, with Rounds down 2% and Fancies down 0.9%. 

That compares with a 9.3% decline in Q1 and a 6.28% decline in Q2. 

The same pattern appeared in larger goods. 

Lab-Grown 2ct prices decreased by 3%, while 3ct prices decreased only 1.1%. In Q1, those same categories had declined by 16% and 15% respectively. 

Lab-Grown prices therefore remained under pressure, but the market was no longer seeing the same level of price erosion that defined earlier quarters. 

After a long period of heavy price compression, Q3 showed a market where further declines were becoming much more measured. 

Key Takeaways 

The Natural market moved from pressure into stability 

Q1 and Q2 were defined by declining prices and selective strength. Q3 was different. Both Rounds and Fancies moved higher, smaller goods recovered, and categories that had been falling began to stabilize. 

The recovery began at the smaller end 

0.30ct and 0.50ct goods showed the strongest price increases of the quarter. What makes that particularly interesting is that they achieved that strength under very different supply conditions, suggesting that the recovery was not simply a result of tighter inventory. 

The US market became easier to price 

Tariffs did not disappear in Q3, but uncertainty around them decreased. Greater clarity around landed costs helped create a more predictable trading environment after months in which changing expectations had affected pricing and confidence. 

Lab-Grown moved closer to stability 

Lab-Grown prices continued to decrease slightly, but the scale of the decline became much smaller. Q3 did not represent a recovery, but it did mark a clear slowdown in the price erosion seen throughout the first half of the year. 

Conclusion 

Q3 2026 was a turning point for the Natural diamond market. 

The quarter did not bring a dramatic rally. It brought something more measured: stability returned, and in some areas stability started turning into recovery. 

The strongest movement came from smaller Rounds, where 0.30ct and 0.50ct prices increased meaningfully. The improvement then extended further up the market. 1ct goods stopped the decline seen throughout Q1 and Q2, 2ct goods regained balance, and 3ct goods continued to show the resilience they had maintained throughout the year. 

The US followed the same broader direction. Tariff uncertainty created another period of volatility in July, but greater clarity around the new tariff structure helped remove one of the largest unknowns facing traders. Prices recovered through August and became more stable into September. 

Q3 was also a period of build-up toward the holiday season, with the market preparing for seasonal demand and expectations that the season would not disappoint. 

Lab-Grown continued to move lower, but even there, the pace of decline slowed significantly. 

The main story of Q3 was therefore not higher prices alone. 

It was a market that finally stopped moving backwards. 

After the pressure of Q1 and the selective stability of Q2, Q3 showed the first signs that stability was broadening into recovery, while also setting the market up for the important holiday season ahead.