Amber clarified

Heat is used to darken amber, ivory, and jade to simulate age. Pieces of amber and tortoiseshell can be reconstmcted, ie, joined under heat and moderate pressure. By careful heating in oil, milky amber can be clarified when the gas and water within small bubbles diffuse out of the stone. If heating is rapid, the attractive sun-spangle cracking shown in Figure 1 results. 

Ultraviolet lig t. Most amber and copal fluoresces in UV lig t (Figs 1.13 and 1.16). This fluorescence dims if the amber has been treated with heat to clarify it or to press it. It also tends to dim and change colour with age - fleshly cut or polished amber will alwa3rs fluoresce more strongly. 

Copal does not undergo treatments to clarify, colour or darken it, as does Baltic amber. 

These results based on comparison of FTIR-VAR spectra about origin of amber artefacts were clarified and confirmed by other non-destructive analysis (Raman, statistical analysis) and supported by historical context, in some cases. In other cases, the assignment of samples to Baltic amber or local (Romanian) amber contributed to understanding of archaeological (historical) context. 

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