amorphous Simulant amber simulant (natural material)

Copal (Amber Simulant)

Formula Partially polymerised plant resin (labdanoid diterpenes; younger resin; not fully matured/polymerised)

Crystal Structure

CDL Notation

 #! Species: Copal (partially polymerised plant resin; amber simulant)
#! System: Amorphous (natural resin)
#! Habit: Irregular nodular masses; resinous
amorphous[resinous]:{nodular}

Crystal System amorphous

Point Group none

Crystal Forms (1)

{nodular}

Quick Facts

Hardness

1.5

Specific Gravity

1.04

Refractive Index

1.53

Optical Character

Isotropic

Physical Properties

Crystal System: amorphous
Hardness (Mohs): 1.5
Specific Gravity: 1.04
Cleavage: None
Fracture: Conchoidal
Lustre: Resinous

Optical Properties

Refractive Index: 1.53
Birefringence: 0
Optical Character: Isotropic
Fluorescence: Often intense (LWUV; typically brighter than amber, but variable)

Origin & Identification

Origin: Simulant
First Produced: 0
Diagnostic Features: Acetone test: surface becomes tacky/sticky in seconds (amber unaffected — definitive field test); softens at lower temperature (~100-150 C vs amber ~200-250 C); FTIR lacks Baltic amber "shoulder" ~1150 cm-1; inclusions appear fresh/undesiccated; surface crazing develops faster; fluorescence often more intense than amber

Characteristics

Colours

Yellow to yellow-orange (similar to amber); pale yellow; transparent to translucent

Common Inclusions

Modern insects (fresh appearancenot desiccated; diagnostic of recent origin); plant matter (less degraded than amber inclusions)

Notes

Partially polymerised plant resin (<40 Ma; often Holocene to Neogene); not fully matured. Key distinction from amber: acetone test — copal becomes tacky/sticky within seconds; amber (fully polymerised) is unaffected. FTIR: lacks the "Baltic shoulder" at ~1150 cm-1 characteristic of mature succinite amber. Rao et al. 2013, Science China Physics, Mechanics & Astronomy (DOI 10.1007/s11433-013-5144-z) [VERIFIED]: amber vs copal by UV-VIS, infrared and Raman spectroscopy — acetone test and FTIR spectral fingerprint confirmed as diagnostic. Commercial sources: Colombia, Madagascar, East Africa, New Zealand. RI essentially identical to amber (1.530-1.545); SG overlaps amber (1.05-1.10); refractometer and float tests cannot reliably distinguish — acetone and FTIR are required.