Diamonds and coloured precious stones are often put in the same category, but they follow very different rules. Understanding the difference is the first step to buying well.
White diamonds: a structured market
The diamond market is inventoried and classified. Every stone can be described by the 4Cs: carat, colour, clarity and cut. Price lists are published, and supply is concentrated among a few large producers. The best known is the Rapaport price list, the reference of the diamond trade. That makes diamonds easy to compare, but it also means prices are largely shaped by the industry itself.
Coloured stones: supply and demand
Rubies, sapphires and emeralds have no single grading standard. Two stones of the same weight can differ enormously in value depending on colour, origin, treatment and the quality of the cut. They come from many small mines, often in remote regions. The supply of fine stones is limited, and the finest are extremely rare.
This is why the coloured stone market rewards knowledge. A buyer who can judge a colour, recognise a treatment and read a laboratory certificate correctly has a real advantage.
What this means for you
- Compare diamonds on their grading certificates.
- Judge coloured stones on colour, origin and treatment, with an expert at your side.
- Favour the top qualities, which have held their value best.