Synthetic, imitation, simulant, composite
“Fake” collapses four distinct categories, and the difference between them is the difference between a stone that is chemically identical to the natural material and one that is coloured plastic. A synthetic is the real mineral, grown rather than mined. An imitation only looks like it, a treated stone is real and altered, and a composite is assembled from parts.
Synthetic
A synthetic has the same composition and crystal structure as the natural mineral. It was grown in a factory rather than in the ground, and by any analysis of what it is made of, it is that mineral. Synthetic quartz is quartz. Its hardness, density and refractive index match the natural material because those properties follow from composition and structure, and both are the same.
This is why synthetics are the hardest category to detect and the least often discussed in consumer guides — there is no property to catch them on except the traces of their growth history. Identification relies on growth features: patterns of internal banding characteristic of the growth method, particular inclusions from the growth vessel, and in quartz the presence or absence of a twinning pattern that almost all natural material shows and most synthetic material does not. These are microscope observations made by a trained examiner, and some of them are difficult even then.
Large volumes of synthetic quartz are grown industrially, principally for electronics, and coloured synthetic quartz for ornament follows the same chemistry. So a piece of clear or coloured quartz being synthetic is entirely plausible and not detectable by anything you can do at home.
The important consequence: a synthetic is not a lesser material in any physical respect. It behaves identically in use. What it lacks is rarity and origin, and those are the whole of the price difference.
Imitation, or simulant
An imitation resembles the material and shares nothing with it. Glass coloured to look like jade. Dyed resin standing in for turquoise. Moulded plastic with pigment. Composition is unrelated, structure is unrelated, and every measurable property differs.
Because everything differs, imitations are the easiest category to catch, and how each type is produced predicts exactly what to look for. Glass carries spherical gas bubbles and flowing internal swirls; it fractures conchoidally. Resin is markedly light and warms fast in the hand. Both are softer than the stones they imitate.
“Simulant” is the more precise word and means the same thing: something standing in for the appearance of a gem without being it. A simulant is honest when it is labelled as one.
Treated
A treated stone is the genuine mineral with something done to it. The species on a report will be correct. Dyeing adds colour. Waxing improves surface polish. Heating alters colour centres. Polymer impregnation fills voids and rebuilds a weakened structure. Irradiation creates colour centres.
Treatments are a spectrum from cosmetic to structural, and the position on that spectrum is what matters. Surface waxing is traditional and accepted in the jade trade; polymer impregnation produces a composite object that degrades as the resin ages, and is classified separately for exactly that reason — the A, B and C system exists to keep this distinction visible.
The category is enormous. Most coloured stone on the market has been treated in some way, much of it by methods so long-established that they are assumed rather than disclosed, and heat, radiation and coating between them account for a great deal of it.
Composite and assembled
A composite is more than one material joined into one object. Historically this meant a doublet or triplet: a thin slice of genuine material cemented to a backing of something cheaper, with the join hidden at the setting. In the stone-tool market the relevant form is reconstituted material — genuine mineral crushed to powder, mixed with resin, dyed, and pressed or moulded to shape.
A reconstituted piece contains real mineral, which is what makes the labelling arguments possible, and behaves like a plastic filled with stone dust, which is what it is. Density is low because resin is much lighter than rock. Under magnification it shows particles suspended in a matrix.
Sorting a stone into the four
WHAT YOU CAN TELL — which of the four
· Bubbles, swirls, mould seams → imitation
· Very light, warms fast, scratches easily
→ imitation, resin family
· Particles in a visible matrix, low density
→ composite, reconstituted
· Colour pooled along cracks → treated, dyed
· Correct hardness and density, no growth
features you can see → natural or synthetic,
indistinguishable at home
· Natural versus synthetic
→ NOT DETERMINABLE at home, and sometimes
difficult in a laboratoryWhy the words get mixed up
The vocabulary is technical and the market is not. Three specific confusions recur.
“Synthetic” is read as “fake”. It is the opposite: synthetic means the composition is right. A listing that says “synthetic” is disclosing more than one that says nothing.
“Genuine” is read as “untreated”. It means only that the species is as named. Dyed jadeite is genuine jadeite.
“Natural” is read as “unprocessed”. Everything sold has been cut and polished; natural refers to origin, not to whether anything was done afterwards.
The result is that the honest words look alarming and the reassuring words carry no content. A seller with nothing to hide often writes a scarier listing than one with everything to hide.
The limit
Three of the four categories leave evidence you can find. Imitations are catchable with a loupe and a kitchen scale, composites by density and texture, most dye by how the colour sits — what those observations do and do not establish is the practical boundary.
The fourth is not catchable. Natural versus synthetic requires microscopic examination of growth features by someone who knows what they are looking at, and for quartz in particular the answer is sometimes unavailable even to a laboratory. If that distinction matters to you, it is a question for a gemmologist, and for most objects at this price the testing costs more than the object.