The same gem can reach you by different routes: formed in nature, grown in a laboratory, improved by treatment, or imitated by another material. Honest jewelry depends on naming each one precisely.
The vocabulary
| Term | Meaning | Example |
|---|---|---|
| Natural | Formed by nature, without human intervention | A mined sapphire |
| Laboratory-grown (synthetic) | Same composition and structure as the natural gem, grown by people | A laboratory-grown ruby |
| Imitation (simulant) | A different material that looks similar | Glass imitating emerald; cubic zirconia imitating diamond |
| Treated | A natural gem whose appearance has been improved | A heated sapphire; an oiled emerald |
| Assembled | Made of two or more parts joined together | Doublets and triplets |
How gems are grown
- Flame fusion (Verneuil process): the oldest commercial method, used for ruby and sapphire since the early twentieth century.
- Flux growth: crystals grow slowly from a molten solution; used for ruby, sapphire and emerald.
- Hydrothermal growth: crystals grow in hot, pressurised water; used for emerald and quartz.
- Crystal pulling (Czochralski): a crystal is drawn slowly from a melt.
- HPHT and CVD: for diamond. Read CVD vs HPHT.
Why disclosure matters
A laboratory-grown gem is a real gem, usually at a much lower price than a natural stone of similar appearance. That is exactly why it must be disclosed: in the United States, the FTC's Jewelry Guides require such stones to be described with words such as "laboratory-grown", "laboratory-created" or "synthetic". DORVETTI always states whether a stone is natural or laboratory-grown, and discloses known treatments.
How laboratories tell them apart
Laboratory-grown gems often carry clues to their growth. Flame-fusion rubies and sapphires can show curved growth lines and tiny gas bubbles; flux-grown stones may contain wisps of flux; hydrothermal emeralds can show distinctive growth patterns. Natural gems contain inclusions typical of their geological origin. Many clues are subtle and need magnification or advanced instruments, which is why disclosure and documentation matter.
Advantages and trade-offs
| Natural | Laboratory-grown | |
|---|---|---|
| Material | The gem species | The same gem species |
| Appearance | Wide range; inclusions typical of nature | Often very clean and consistent |
| Rarity | Finite | Produced to order |
| Price | Higher for comparable appearance | Usually much lower |
| Disclosure | Treatments must be disclosed | Laboratory origin must be disclosed |
Treated gems
Many natural gems are treated to improve colour or clarity: heating of sapphires and rubies, oiling of emeralds, irradiation of some topaz. Treatments are part of the trade and are not necessarily negative, but they affect value and care, so they must be disclosed.
Asking the right questions
- Is this stone natural or laboratory-grown?
- Has it been treated, and how?
- Is there a report from an independent laboratory?
- Does the treatment require special care?
Sources: Gemological Institute of America (gia.edu), gem encyclopedia; US Federal Trade Commission, Guides for the Jewelry, Precious Metals, and Pewter Industries, 16 CFR Part 23.
Frequently asked questions
Is a synthetic gemstone fake?
No. In gemmology, synthetic means laboratory-grown: the same material as the natural gem. An imitation is a different material.
Can a laboratory tell natural from lab-grown?
In most cases, yes, using growth features and trace elements that are invisible to the eye.
Are lab-grown gems cheaper than natural ones?
Usually much cheaper for a comparable appearance, because they can be produced to order.
Are treated gems fake?
No. They are natural gems whose appearance has been improved. The treatment must be disclosed.
