Reading a report

Every important stone we publish arrives with a laboratory report. Before you read it, we read it, and we do not treat it as a stamp: we treat it as an X-ray. A good report does not say “this stone is beautiful”. It says what it is, whether it was born from the earth, whether someone helped it afterwards, and — sometimes — where it comes from. Those are four separate questions, and it pays to keep them apart.

Species and variety

The first line that counts is the identification, and it comes in two levels. The species is the mineral group, defined by chemistry: corundum, beryl, garnet. The variety is the trade name tied to colour within that species. Ruby and sapphire are the same mineral, corundum: the colour changes, not the species. Emerald and aquamarine are both beryl. Tsavorite is a grossular garnet. 1 When a seller uses the variety name without the species behind it, they are not necessarily lying, but they are giving you half the information.

Natural, first of all

The second question is whether the stone is natural or synthetic. A synthetic gem has the same chemistry and the same structure as the natural one: it is true corundum, true beryl, only grown in a laboratory in weeks instead of millions of years. With synthetic production rising in recent years, this line has become the most important of all. 2 The laboratory settles it by looking inside: inclusions, growth lines and chemical traces reveal whether the crystal formed in rock or in a furnace. A serious report writes “natural” in plain words, or declares it laboratory-grown.

Treatments, declared

The third question is what happened to the stone after it was mined. Most sapphires and a large share of rubies on the market have been heat-treated: controlled heat to open the colour or dissolve inclusions. It is an accepted treatment, but it must be written down. On corundum the report uses a precise phrase — “no indications of heating” — when the stone has never seen the furnace.

An unheated ruby or sapphire, at equal quality, can be worth 60 to 100 per cent more than a heated one. That single line is worth more than many others.

The premium for “unheated” is real and measurable, which is why that single phrase moves the price more than another half-carat would. 3 A report that stays silent on treatments is not more elegant: it is less useful.

Origin, when there is one

The fourth question is geographic, and it is the one most often muddled. Origin is not available for every stone: laboratories determine it for a short list — sapphire, ruby, emerald, alexandrite, Paraíba tourmaline and red spinel — to which peridot, opal and demantoid are added from 2026. 4 And even when it exists, the report gives a country or an area, never the single mine: trace chemistry and inclusions carry that far, no further. A report that promises the name of the pit is promising something the science does not give.

When a stone in our catalogue has a report, we attach it and walk you through it, line by line. When it has none, we say so, and we tell you why. A report read well is not there to close the conversation: it is there to open it.