OK, a phenolic resin distributor (Parkway Products) tells us that phenolic resins are resistant to common organic solvents, including acetone, which is commonly available as nail polish remover.

"Copal will dissolve in acetone." says amber collector Garry Platt, so this might make a simple household test to distinguish between copol and phenolic resins. See http://www.amberjewelry.com/Identifying_True_Amber_Gary_Platt.htm.

Platt lists a number of tests to distinguish from amber--I recommend his site and I'm going to try several of these tonight.

Finally, in 1995 Anderson and Crelling classified amber/copol into eight categories, based on the extent of their fossilization (i.e., polymerization). This well-referenced and scientifically-based website gives one of the best technical discussions of copol and amber that I have seen.

Have a good one. Nancy