Diamonds

$675 for the one-carat while the index rises $12: lab-grown splits in two

CaratRadar's one-carat average fell $12 to $675, a third straight lower mark from Monday's $700. Its whole-market index rose $12 to $1,535 over the same day, and active listings passed 1.21 million.

By The Diamond Desk

What changed

CaratRadar's page, read directly by this desk at press time, puts the one-carat lab-grown average at $675 as of 2 September. That is $12 below Tuesday's $687 and $25 below Monday's $700, a fall of 3.57% across three readings.

What it means

  • Three lower marks in a row at the one-carat point, against a whole-market index that rose on the same day, is not a collapse and should not be sold to a customer as one. What it is, on this evidence, is a one-carat segment carrying more stock than it can clear at last week's asking prices while the rest of the marketplace holds.
  • The practical consequence for a retailer is narrow and immediate. The one-carat lab-grown stone in the case is being asked for less than it was on Monday, and nothing on this page says the same is true of the sizes sitting beside it.

Key figures

one-carat average, from $687$675
market price index, from $1,523$1,535
active listings in a day1,211,846
one-carat, across three readings from $700-3.57%

Source: CaratRadar's lab-grown page, read at press time

A $13 step, then a $12 step

This paper reported on Tuesday that the $13 step from $700 to $687 was the largest single-day move the reference had made since this tape opened on 5 August, when every prior move had been three dollars or less. It has now been followed by a $12 step in the same direction.

one-carat average, from $687$675

CaratRadar one-carat lab-grown average, USD

31 Aug$700
1 Sep$687
2 Sep$675

Source: CaratRadar's lab-grown page, read at press time

The same twelve dollars, the other way

The more interesting number is the one moving the other way. The same page puts the market price index at $1,535 on 2 September against $1,523 on 1 September, a rise of $12 or 0.79%. The one-carat average and the whole-market index moved by the same twelve dollars, on the same day, in opposite directions.

The index spans every size and grade on the marketplace. The one-carat average spans one size. The two diverge when the mix moves, not when the market falls as a whole, and on this reading the mix is what moved.

CaratRadar one-carat lab-grown average, USD
Figure
31 Aug$700
1 Sep$687
2 Sep$675

Three readings, $25 or 3.57%. Every move on this reference before 1 September was three dollars or less. CaratRadar page text, read directly by this desk on each date. Carat Capital graphics desk.

Seven thousand more stones in a day

Supply is the third figure and it points the same way. Active listings went from 1,204,718 on 1 September to 1,211,846 on 2 September, 7,128 more stones in a day, up 0.59%. Listed prices run from $51 to $1,503,988.

More goods on offer while the average asking price at one specific size falls is the ordinary shape of a segment clearing inventory. It is a different condition from a market repricing across the board, and the two should not be reported as the same event.

Three prices that are not one price

One caution on reading these numbers against this paper's own price chip. The LGD1 chip on the tape is drawn from a separate wholesale file and prints the midpoint of a CVD wholesale band, $475.00, dated 30 July 2026 on that file.

CaratRadar's $675 is an average of asking prices across a marketplace of live listings, read today. They are not the same measurement, they are not from the same week, and they should not be netted against one another.

A listings average tells you what sellers are asking. A wholesale band midpoint tells you roughly what the trade pays.

The story so far

  1. $687 in one step: a one-dollar drift becomes a thirteen-dollar fall (1 September 2026)
  2. £59,000 in Penzance: a steel Patek beats its low estimate 11.8 times
  3. 1,600 square feet at South Coast Plaza: Jessica McCormack takes the West Coast

Go deeper

Method

Three readings, $25 or 3.57%. Every move on this reference before 1 September was three dollars or less.

Sources1