When a jeweller quotes a stone, the number is not a guess and it is not a secret — it comes from a small set of trade benchmarks that the industry has built over decades. Knowing they exist changes how you read any gem price, from the 4 Cs of diamonds to a gem certificate.
Diamonds: the Rapaport benchmark
The Rapaport price list is the international benchmark dealers use to establish diamond prices across all major markets. Subscribed to by dealers and jewellers, it states current market prices by size, colour and clarity, is updated weekly, and reflects changes in the global diamond markets. It is often used openly with customers — and in practice serves as the basis from which recommended retail prices are discounted. Alongside it, Diamonds.net offers subscription price lists that compare the Rapaport sheet in real time against the average and best prices of live listings on RapNet, the Rapaport diamond trading network.
The source that beats every chart
For actual cost prices, there is no substitute for speaking to a supplier: diamond dealers in Singapore provide price lists to qualified businesses, along with advice on payment methods and terms. Charts give the shape of the market; conversations give the number.
Coloured gems: the Gem Guide and friends
Coloured stones have their own authorities. Gemworld's Gem Guide — from a company with thirty years of supplying prices to the industry — is the reliable benchmark for independent, market-driven wholesale pricing, available by subscription in print and online. GemVal pioneered online gemstone valuation as a further reference point. Where diamonds price off one dominant sheet, coloured gems reward knowing several sources — which is itself part of how gem value is judged.
Why this matters at the counter
These benchmarks explain two things shoppers notice. First, why stone quotes move week to week: the underlying lists do. Second, why two jewellers can quote differently for similar stones: each starts from the same benchmarks but lands on different terms from suppliers. Combined with metal-weight estimation and the worked example in why jewellery costs more than its materials, they complete the professional picture of where a price tag actually comes from.