Knowledge
Natural, synthetic and imitation material
Three terms that are often confused: what they mean, how a laboratory tells them apart and why the classification must never rest on assumption.
A ruby may have grown in the earth, been grown in a laboratory or be imitated by an entirely different material. To the eye the difference is often invisible. That makes precise use of the terms all the more important.
Natural
Natural gemstones formed in geological processes without human involvement, often over millions of years. A later treatment – such as heating – does not change the fact that the material is natural, but it must be disclosed.
Synthetic
Synthetic stones are grown in a laboratory and have essentially the same chemical composition, crystal structure and physical properties as their natural counterpart. A synthetic ruby is therefore corundum – only grown. Common methods are flame fusion, flux growth and hydrothermal growth; for diamonds, high-pressure high-temperature synthesis (HPHT) and chemical vapour deposition (CVD). Under the industry's nomenclature rules a synthetic stone must always be described as such, for example as "laboratory-grown" or "synthetic".
Imitation
An imitation only copies the appearance, for example glass that looks like emerald, or cubic zirconia in place of diamond. Its chemistry and properties are different. Imitations can usually be recognised with standard instruments such as the refractometer or the microscope.
How a laboratory distinguishes them
Separating natural from synthetic is more demanding. Evidence comes from inclusions and growth features under the microscope, spectroscopic signatures and trace elements. For diamonds, specialised instruments are now part of standard equipment. The result is a reasoned finding, not a guess.
In brief
Natural means formed in the earth, synthetic means grown in a laboratory with the same chemistry, and an imitation only copies the appearance. The eye often cannot tell them apart. What counts is the finding of an independent laboratory, not the description in an offer.
At NOBILITH
NOBILITH offers only natural gemstones with a report from an independent laboratory. If a stone is treated, the dossier says so – in the laboratory's wording, not a simplified version.
Sources
- CIBJO: The Gemstone Book and The Diamond Book (nomenclature)
- ISO 18323: Jewellery – Consumer confidence in the diamond industry
- GIA: Gem Encyclopedia, articles on synthetic gemstones
Read more
- Laboratory reportsUnderstanding a laboratory reportA laboratory report is a gemstone's most important document. Which information it contains, how to read it and what it does not say.Read more
- Gem LabGemmological microscopeThe most important instrument in the laboratory: under the microscope, inclusions, growth features and signs of treatment become visible.Read more
- KnowledgeHow to read a gemstone dossierA dossier brings together everything that describes a stone – from the laboratory report to custody. Here is how to read it in the right order.Read more
- KnowledgeWhy colour changes under different lightThe same stone can look different in daylight than under a lamp. The reason lies in the interplay of light source, absorption and the eye.Read more
Updated 2026-10-06