% Off Rap — The Discount Convention That Drives Diamond Pricing
% Off Rap — The Discount Convention That Drives Diamond Pricing
Diamond trade shorthand for pricing relative to the Rapaport Diamond Report, the de facto industry price benchmark
The phrase % off Rap (or off Rap or Rap minus) is the standard pricing shorthand in the diamond trade, expressing a discount relative to the Rapaport Diamond Report price list. The Rapaport list, published weekly by Rapaport USA Inc. since 1978, sets reference prices per carat for polished diamonds across colour and clarity grades at common weight categories. A stone offered at Rap minus 28 or 28 off Rap is priced at 72 percent of the Rapaport list value for its weight, colour, and clarity grade. The convention is the working language of business-to-business diamond pricing internationally.
How the Rapaport list works
The Rapaport list is a matrix of prices per carat organised by colour grade (D through M and below for higher categories), clarity grade (IF through I3), and weight category (typically half-carat increments through 1.99 carats, then 2.00 to 2.99, 3.00 to 3.99, and broader categories above). Each cell of the matrix carries a price per carat in U.S. dollars. The list is updated weekly to reflect market conditions, with periodic structural revisions.
The list is intended as a wholesale reference, not a retail price guide. Retail markups vary widely by jurisdiction, retailer, and product positioning, and Rap-based pricing is not generally communicated to consumers directly. The list is widely subscribed to by diamond dealers, manufacturers, and bourse members, and is updated through the RapNet electronic trading platform, which allows real-time visibility of offers and asks against the published list.
Reading off-Rap pricing
An offer described as Rap minus 28 means the seller is offering the stone at 72 percent of the listed Rapaport value. Equivalently, this can be stated as 28 off Rap, 28 percent below Rap, or Rap minus twenty-eight. Discounts are the norm in the trade; the listed Rap price is rarely paid in business-to-business transactions, with even premium stones typically transacting at small discounts to Rap.
Premiums above Rap are denoted as plus or over Rap: a stone Rap plus 5 trades at 105 percent of Rap. Premium pricing applies to particularly desirable stones — fine cuts at higher quality grades, fancy colour diamonds, stones with exceptional symmetry or fluorescence characteristics, and certified rounds with strong cut grades — but is the exception rather than the rule.
Factors driving the discount
The discount applied to a specific stone reflects multiple factors. Cut quality is one of the largest: a triple-Excellent (Excellent cut, polish, and symmetry) GIA-graded round at the same weight, colour, and clarity grade may trade at a substantially smaller discount than a Good or Very Good cut stone. Fluorescence can move pricing in either direction depending on stone size and grade. Inclusion characteristics within a clarity grade affect pricing — eye-clean SI1 stones command better pricing than visibly included SI1 stones at the same carat-colour-clarity grade.
Beyond stone-specific factors, market conditions shift discounts. Periods of soft demand widen discounts; periods of strong demand narrow them or even produce premiums above Rap. The Rapaport list itself is updated to reflect these conditions, but day-to-day market sentiment moves discounts within the period between list updates.
Rapaport's role in the trade
The Rapaport list and RapNet platform have, over four decades, become the de facto pricing infrastructure for the polished diamond trade. Critics have argued that the list's structure and its publisher's commercial interests create conflicts that distort pricing, but the practical centrality of the list to trade conversation has not been displaced by alternatives. Other pricing tools and platforms — IDEX, GIA pricing reports, various proprietary pricing models — operate alongside Rap but generally reference Rap-equivalent pricing in their structures.
Lab-grown diamond pricing has developed its own conventions, with separate published lists and discount structures reflecting the substantial price differential and the different market dynamics of synthetic stones.