Fossil tree resin, and the one material in this room with a decisive home test: it floats in salt water.
The Baltic coast, the Dominican Republic, Myanmar, Mexico7 field tests
Amber is tree resin that has polymerised and lost its volatile components over tens of millions of years. It is not a mineral — it is organic, and it was alive — which is why it behaves unlike everything else in this room: it is warm to the touch, light enough to float, soft enough to scratch with a fingernail, and it burns.
It is also faked more thoroughly than almost anything else, in four distinct ways. Plastic — usually polyester resin, phenolic or casein — is moulded to look like it. Copal, which is genuine tree resin but only thousands to a few million years old rather than tens of millions, is sold as amber. Pressed or reconstituted amber is real amber powder fused under heat and pressure. And 'inclusions' are manufactured, by embedding modern insects in resin.
The saving grace is that amber's low density gives it a test almost nothing else in gemmology has: a decisive, free, at-home separation. Amber's specific gravity is about 1.05 to 1.09. Saturated salt water is about 1.15. Amber floats. Most plastics and all glass sink.
Dissolve as much table salt as will go into warm water — roughly two heaped tablespoons per cup, stirred until no more disappears — and let it cool. That brine reaches a specific gravity of around 1.15, which sits neatly above amber and copal and below almost every imitation.
Genuine amber and copal float, often just breaking the surface. Polystyrene may float too, so a float result should be confirmed with one more check. Polyester resin, phenolic plastics, casein, glass and every mineral sink. Rinse the piece in fresh water afterwards, because dried salt dulls the surface.
| Material | Salt water | Hot pin smell | Other behaviour |
|---|---|---|---|
| Baltic amber (30–50 million years) | Floats | Sweet, resinous, like pine incense | Warm to touch; static lift after rubbing; fluoresces blue under UV |
| Copal (young resin) | Floats | Sweet and resinous, but softer and quicker | Softer, tackier under solvent; often too-perfect insects |
| Pressed / reconstituted amber | Floats | Resinous — it is amber | Elongated 'sun spangle' bubbles; flow lines under a loupe |
| Polyester or phenolic resin | Sinks | Acrid, chemical, like burning plastic | Mould seams; round bubbles; no static lift |
| Glass | Sinks | Nothing — it does not melt | Cold to the touch; hardness 5.5; scratches nothing |
The two tests in the middle columns, run together, separate the field. Neither is difficult and neither needs equipment beyond salt, a pin and a lighter.
Ordered by how much each one proves. The decisive tests are worth your first two minutes; the supporting ones only matter once those agree.
This is the best single test available for any material the house reads. Saturate warm water with table salt, let it cool, and drop the piece in. Amber at 1.05–1.09 specific gravity floats or hovers just under the surface; polyester resin, phenolic plastic, casein and glass all sink. Rinse in fresh water afterwards. The one caveat is polystyrene, which is light enough to float too, so pair a float result with the hot-pin test.
Heat a needle and press it briefly into an inconspicuous place — inside a drill hole, or on the back of a bead. Amber and copal give a distinctly sweet, resinous, incense-like smell, because that is exactly what they are. Plastic smells acrid and chemical. Glass does nothing at all. This is destructive on a microscopic scale, so do it once and out of sight.
A fossil inclusion is the most valuable thing amber can contain and therefore the most manufactured. Genuine inclusions are usually incomplete, distorted, partly decayed, often accompanied by debris, bubbles and stress fractures radiating from the body, and the creature is typically in a natural struggling posture. A manufactured inclusion is a whole, perfect, recognisable modern insect, cleanly centred, with no surrounding debris — and frequently far too large. If it looks like a museum display, it was made to.
Amber is strongly triboelectric — it takes a static charge readily, enough to pick up small scraps of tissue paper or hair. The Greek word for amber, elektron, is where the word electricity comes from, which is a fair indication of how characteristic this is. Most plastics take a weaker charge and glass essentially none. Rub for twenty seconds on wool or your sleeve first.
Baltic amber fluoresces a distinct pale blue to blue-white under longwave ultraviolet, sometimes strikingly. Copal fluoresces much more weakly, usually a dull whitish. Most plastic imitations do not fluoresce in that way at all, though some fluoresce a flat white. A cheap UV torch makes this a two-second check.
Amber is 2–2.5 on the Mohs scale — a fingernail at about 2.5 will just mark it, and a copper coin certainly will. That softness also means genuine worked amber is cut and polished, never moulded, so a faint seam line, a flat sprue mark, or two matching halves with a join indicates a cast. Run a fingertip around the piece's equator.
Pressed amber — real amber powder fused under heat and pressure — is given away by its bubbles. They are drawn out into flattened, disc-like 'sun spangles' by the pressing, and the piece often shows faint flow lines or a slightly mottled, marbled structure where the fragments merged. Natural amber's bubbles are round or irregular and randomly placed.
Amber has been imitated for as long as it has been traded, and the industry is mature. The high end of the fraud is Dominican and Burmese material with manufactured inclusions, where a genuine piece of young resin receives a modern insect and a very large price. The volume end is Baltic-style beads in polyester resin sold at markets and online in their thousands.
There is also a large, legitimate, poorly disclosed middle: pressed amber. It is genuine amber, reconstituted from fragments, and it is a perfectly reasonable product sold honestly. Sold as natural Baltic amber at natural prices, it is not.
One further note, because it comes up: 'amber' teething necklaces and the associated claims are outside what the house will comment on. The material question is the same as any other bead.
Each of these is checked differently. The ones with their own page have enough that is specific to them to be worth reading separately.
Specimen figures rather than gem figures, for material in honest condition. Most finds are worth very little, and saying so plainly is more useful than encouraging you.
| Material | What it typically fetches | Note |
|---|---|---|
| Resin or plastic imitation | Nothing | A few dollars a strand at a market |
| Copal, no inclusion | $5 – 30 a piece | Honest under its own name |
| Pressed amber beads | $10 – 60 a strand | Genuine amber, reconstituted |
| Natural Baltic amber, clean | $30 – 300 a piece by size and clarity | Colour and clarity |
| Baltic amber with a genuine insect | $80 – 1,000+ | Species, completeness, clarity |
| Scientifically significant Burmese specimen | Five figures and above | A research object, not jewellery |
Amber prices are set by inclusions above everything else, which is precisely why inclusions are the part most often manufactured. Burmese amber also carries sourcing questions that a buyer should ask about independently of authenticity.
Lovenhall StoneThe tests tell you what it is. The instrument reads a photograph and offers a name to start from — then hands you back to the tile and the coin, which are what settle it.