Some call them “oversizes.” Others call them “off-sizes” or “premium sizes.” Whatever the label, they’re one of the hot items amid the latest diamond-industry downturn.
All three terms refer to polished with a weight just shy of a round number. Examples include 1.30 to 1.49 carats, close to the 1.50-carat mark, as well as 2.50 to 2.99 carats, popular with those seeking the appearance of a 3-carater.
Their desirability in the US bridal market is not new. For many years, consumers have seen them as a way to get a larger look at a lower price point. Dealers and manufacturers can sell them faster than other goods. They are not exactly booming, but they have seen less of a price drop than other sizes during the 2024 crisis, traders say.
These categories are “holding the fort in terms of getting [narrower] discounts,” said Nilesh Chhabria, chief operating officer at Mumbai-based manufacturer Finestar Jewellery & Diamonds. “They pull a premium price [in terms of discounts off the Rapaport Price List].”
There is disagreement about exactly why. Some point to budget-conscious consumers and the keenness of dealers to get their hands on popular items. Some highlight production cuts in India and shortages of the rough.
Non-linear pricing
The pricing structure of natural diamonds enables this phenomenon.
Larger diamonds are naturally more expensive per carat than smaller ones due to their rarity. However, if you were to draw a graph of how prices progress with size, it would resemble the side view of a badly built flight of stairs rather than a ramp.
Diamonds are bundled into discrete size brackets. The Rapaport Price List, for example, has one per-carat price for 1- to 1.49-carat diamonds and another for 1.50 to 1.99 carats. After 2 carats, the next step up is 3 carats.
This means there’s a big price jump from 0.99 to 1 carat, from 1.49 carats to 1.50 carats, and so on.
This has two logical impacts on the sizes that just miss these thresholds. On the one hand, it’s like buying last year’s iPhone a week before the new model comes out. You’d expect a big discount. On the other hand, the fact that it’s cheaper itself generates demand.
The G, VS2 case study
It’s more complicated than this, however, as the price jumps will vary between different bands.
For example, a round, 1- to 1.49-carat, G-color, VS2-clarity diamond is 29% more expensive per carat on the current Rapaport Price List than a 0.90 to 0.99-carat stone with the same other features. The increase to the next band, 1.50 to 1.99 carats, is 65%. Someone buying an equivalent 2- to 2.99-carat stone would have to pay 52% more per carat, while the step up to 3 carats is another 56%.
Therefore, in percentage terms, and in these quality criteria, a customer has the most to gain from what’s called the 1-carat oversize, which usually refers to around 1.25 to 1.49 carats. This is because the jump to the 1.50-carat price is so large that there is a big incentive to stay below it.
These price relationships change over time and can influence how popular the different oversizes are. They also vary by color and clarity.
Three years ago, the structure of diamond pricing was rather different. According to the Rapaport Price List on January 7, 2022, the leap from 90-pointers to a whole carat was larger, at 48%. But the gaps higher up the ladder were narrower: There was a 26% premium for 1.50 carats over the previous level, 41% for 2 carats, and 42% for 3 carats.
Why the market’s structure changed is a topic in itself, but the apparent impact on oversizes is visible in some categories.
At this point, actual average asking prices on RapNet come into play.
The premium for a 0.95- to 0.99-carat diamond in the same round, G, VS2 bracket — compared with 0.90 to 0.95 carats — has not seen an overall increase during those three years, according to data based on the platform’s asking prices (see graph). This is consistent with the narrowing of the gap on the Rapaport Price List between 1 carat and the next price down.
However, the premiums for 1.25-carat to 1.49-carat and 2.50- to 2.99-carat goods relative to the next price band down have risen strongly, according to the asking-price data.
The key exception is the 1.70- to 1.99-carat band, for which premiums over 1.5 to 1.69 carats were at the same level in January 2025 as they were in the January 2022, though they did climb during 2024.
Demand and supply
The structural factors operate in tandem with other market forces. Inflation and high interest rates over the past two years have pushed consumers to seek cheaper deals — and while this has helped the synthetics sector, it has also heightened demand for oversizes relative to other goods. China’s slowdown has also boosted the importance of the US — the main market for oversizes — relative to the rest of the world.
Decades ago, the category was harder to sell. Greater public knowledge of diamonds has changed that. Consumers can compare prices in a few clicks and find tips on getting good deals from numerous websites. They have come to understand the importance of spread — how big the table appears — rather than just carat weight.
Meanwhile, overall polished production in India fell by around 50% in the second half of 2024, leading to less availability of oversizes in absolute terms.
Manufacturers give different reports about whether output of oversizes dropped proportionately.
Some say the share of production for off-sizes has increased during the downturn because manufacturers know they move faster and at more favorable discounts than other items. Others say companies would prefer to hit the round carat size if they can, because the dollar price is higher, but dealers and retailers will snap up the off-sizes when they come on the market.
“Once it is already polished, everyone wants to buy the oversizes, because you pay the price from the 2-carat list for something that looks closer to the 3 carat,” said Ari Jain, chief financial officer of New York-based manufacturer and dealer House of Diamonds.
Still others say manufacturers prefer to make a 2.80-carat triple Ex diamond — with excellent cut, polish and symmetry — than a 3-carater with inferior grades.
The simple fact that manufacturers have an interest in reaching the higher size threshold, all other things being equal, creates a predictable shortage. The rough that produces them is also hard to find. You cannot buy parcels of oversize rough. Manufacturers source them individually or receive them inside larger assortments of goods.
Name game
The result is a peculiar situation where diamonds that miss the “magic numbers” — sometimes by a little, sometimes by more — are in fact in demand for that very reason.
The rise of the perhaps confusing term “oversize” — emphasizing that the diamond is at the larger end of a price range — reflects this positive representation of the category. The word “off-size,” while still common in the trade, stresses the inadequacy of a diamond that falls short of a size threshold.
“In today’s world, they’re desirable,” said Ronnie VanderLinden, president of New York-based polished manufacturer Diamex and of the International Diamond Manufacturers Association (IDMA). “They’re premium sizes.”
Image: Polished diamonds. (Shutterstock)
