A Beginner's Guide to Natural Gemstones
Natural, treated and synthetic stones — and why the difference matters for value.
Natural gemstones form in the earth. Synthetic stones have the same chemistry but are grown in a laboratory, and simulants only imitate the appearance of a gem.
Many natural gemstones are treated to improve colour or clarity — for example heating of sapphires and rubies or oil filling in emeralds. Treatment is common and accepted, but it must be disclosed because it affects value.
The main value factors are colour, clarity, cut, size and origin. For important stones, a report from a recognised gemmological laboratory helps confirm identity and any treatment.
Ask your supplier to state in writing whether a stone is natural, whether it has been treated, and what documentation accompanies it.