Amber
Amber fossilised tree resin including Baltic, Dominican, and Burmese varieties with inclusions, identification, and distinguishing from copal.
Introduction
Amber is fossilised tree resin (an organic hydrocarbonate polymer with no fixed chemical
formula) derived from ancient coniferous trees and aged 20–100+ million years. Amorphous
rather than crystalline, it has no crystal system. Diagnostic properties: hardness 2–2.5
Mohs, SG 1.05–1.10 (floats in saturated salt water), spot RI approximately 1.539–1.545
with a resinous lustre; values that distinguish amber from glass simulants (SG ~2.4) and
plastic. Colour ranges from pale yellow and honey to deep cognac and cherry-red, occasionally
blue in Dominican material due to polycyclic aromatic hydrocarbon fluorescence. Baltic amber,
the world's most abundant source at 40–50 million years old, contains 3–8% succinic acid,
a unique chemical marker separating it from younger copal, which dissolves on contact with
acetone whereas true amber is unaffected. [1] Inclusions of insects, plant
fragments, or air bubbles dramatically raise specimen value; Burmese amber at ~100 million
years preserves Cretaceous biodiversity of unique scientific significance. [2]
Formation and Composition
How amber forms:
Formation Process
- Tree exudes sticky resin (response to injury)
- Resin may trap insects, plant material, debris
- Resin is buried by sediment
- Over millions of years, polymerisation occurs
- Volatile compounds evaporate; resin hardens
- Becomes amber after ~2–10 million years
Composition
- Organic polymers: No fixed chemical formula
- Main components: Carbon, hydrogen, oxygen
- Variable: Composition differs by source tree
- Succinic acid: Baltic amber contains 3–8% [2]
Physical Properties [1]
| Property | Value |
|---|---|
| Hardness | 2–2.5 Mohs (very soft) |
| Specific gravity | 1.05–1.10 (floats in salt water) |
| Refractive index | 1.539–1.545 (spot) |
| Lustre | Resinous |
| Fracture | Conchoidal |
| Static electricity | Attracts paper when rubbed |
Major Sources
| Source | Age | Characteristics |
|---|---|---|
| Baltic (Europe) | 40–50 million years | Yellow to cognac; succinite; most common |
| Dominican Republic | 20–30 million years | Blue fluorescence; rare blue amber |
| Myanmar (Burmese) | ~100 million years | Cretaceous; scientifically valuable |
| Mexican (Chiapas) | 20–30 million years | Similar to Dominican |
| Indonesian | 20–30 million years | Various qualities |
Colour Varieties
Amber occurs in many colours:
Common Colours
- Honey/cognac: Most common; warm golden brown
- Yellow: Light to golden yellow
- Cherry: Reddish-brown; treated or natural
- Green: Rare; natural or treated
- White (bone): Opaque; from micro-bubbles
Blue Amber
Dominican blue amber is exceptionally rare:
- Appears normal in transmitted light
- Shows blue fluorescence in UV/sunlight
- Caused by polycyclic aromatic hydrocarbons
- Commands significant premiums
Inclusions
Amber famously preserves ancient life:
Biological Inclusions
- Insects: Flies, ants, beetles, wasps, spiders
- Plant material: Leaves, flowers, seeds, pollen
- Hair/feathers: Rare; scientifically important
- Air bubbles: Common; create cloudiness
Value of Inclusions
Inclusions can dramatically increase value:
- Rare or unusual specimens: Exceptional prices
- Well-preserved, visible insects: Premium
- Multiple inclusions in one piece: Valuable
- Scientific importance: Museum interest
Common inclusions (gnats, air bubbles) add less value.
Amber vs Copal
Identification Tests
| Test | Amber | Plastic/Glass | Copal |
|---|---|---|---|
| Salt water float | Floats (SG ~1.08) | Usually sinks | Floats |
| Hot needle | Piney, resinous smell | Chemical/acrid smell | Softer, sticky |
| UV fluorescence | Blue-green (Baltic) | Often orange/none | Variable |
| Acetone test | No effect | May damage surface | Surface softens |
| Static electricity | Attracts paper | May or may not | Attracts paper |
Treatments
Common amber treatments:
Clarification
- Heat/pressure treatment to clear cloudy amber
- Creates "sun spangles" (disc-shaped stress marks)
- Very common; accepted practice
- Often not disclosed
Other Treatments
- Dyeing: Changes colour (especially green, cherry)
- Heated/pressed: Reconstituted from small pieces
- Coated: Surface enhancement
- Filled: Repairs or creates fake inclusions
Fake Inclusions Warning
Care and Durability
Amber requires gentle handling:
- Hardness: 2–2.5 (very easily scratched)
- Solvents: Avoid alcohol, perfume, hairspray
- Heat: Can crack or cloud
- Sunlight: May darken over time
- Cleaning: Warm water, soft cloth only
- Storage: Keep away from harder gems
References
- ↑ 1. Read, P. (2008). Gemmology (3rd ed.). Butterworth-Heinemann. ISBN: 978-0-7506-6449-3. DOI: 10.4324/9780080507224.
- ↑ 2. Anderson, K.; Botto, R. (1992). The nature and fate of natural resins in the geosphere—II. Identification, classification and nomenclature of resinites. Organic Geochemistry, 18(6), 829–841. DOI: 10.1016/0146-6380(92)90051-x.