Basic Physical and Buoyancy Tests
Amber is fossilized tree resin, an organic gemstone formed through polymerization over millions of years. Because of its value, materials like younger resins (copal), plastics, and glass are often passed off as genuine. Learning how to check these differences is important for authentication, given the prevalence of convincing counterfeits.
The easiest, non-destructive method relies on a simple test of density and buoyancy. Genuine amber possesses a low specific gravity, typically around 1.08, which is significantly lower than most imitation materials. To perform the buoyancy test, create a supersaturated solution by dissolving salt into water—about one part salt to two parts water—until no more salt dissolves.
This saline solution achieves a specific gravity of approximately 1.13, causing true amber to float readily. Most common imitations, such as plastics, possess a higher density and will sink to the bottom. Glass sinks immediately, making the buoyancy test an effective initial screening method.
Basic physical checks offer further clues. Amber feels notably warm to the touch because it is a poor conductor of heat, unlike cold glass or stone. The material is also very light for its size. Closer inspection may reveal natural inclusions like small insects or perfectly round air bubbles formed under pressure.
Solvent and Ultraviolet Light Checks
Testing a specimen’s chemical stability provides confirmation using common organic solvents like acetone. Genuine amber, due to its complete polymerization, is highly resistant to these chemicals and remains unaffected.
Apply a drop of acetone, typically found in nail polish remover, to a discreet area. Check the surface for change after a few moments. If the material is a younger resin, such as copal, the solvent will cause the surface to become tacky or sticky because the resin has not fully hardened.
Exposing the specimen to ultraviolet (UV) light is another non-destructive technique. The chemical structure of true amber causes it to fluoresce when exposed to UV light. Most authentic amber will emit a distinct color, often blue, green, or chalky white-yellow.
This reaction is a reliable indicator, as most plastics and glass fakes show no reaction. Copal rarely exhibits the same level of fluorescence as fully fossilized amber, often appearing inert or only faintly reactive.
The Heat and Odor Test
A slightly destructive, but definitive, test involves applying heat to elicit a characteristic odor. This method uses a hot needle, heated until glowing red, which is gently pressed into an inconspicuous spot. The material’s reaction and resulting scent provide evidence of its composition.
When the hot needle touches genuine amber, it produces smoke and emits a distinct, pleasant aroma. This scent is a faint, resinous odor reminiscent of pine or burning incense. The material resists melting and is difficult to penetrate with the needle.
The odors from imitations are immediately distinguishable. If the material is plastic, the smell will be acrid and chemical, characteristic of burning synthetic polymers, and the needle will easily melt the surface. Copal produces a sweeter scent than amber, but it softens and melts more readily than fully fossilized amber.
How Imitations Differ from True Amber
The effectiveness of these verification methods stems from fundamental differences in material composition. Copal is the most common imitation; it is a younger tree resin that has not undergone complete polymerization. Because of its youth, copal retains volatile organic compounds, causing it to soften in acetone and release a different scent profile when heated compared to true amber.
Plastic counterfeits are synthetic polymers manufactured to mimic amber. These fakes fail the buoyancy test because their specific gravity is much higher than natural amber, causing them to sink in saltwater. Their synthetic nature means they emit a harsh, chemical smell when heated, and they lack fluorescence under UV light.
Glass is typically distinguished by its high density and cold tactile feeling. Glass sinks in both freshwater and saltwater. Unlike amber, which is relatively soft (scoring 2 to 2.5 on the Mohs scale of hardness), glass cannot be scratched with a metal tool. Glass imitations are also inert to both solvents and heat.