@littlek,
What you find on the beach is anything from browinsh to golden yellows and the amber looks like a hunk of plastic or a busted beer bottle.
The piece in the pic is a cabachon done by cutting a slab of the amber and then gluing it to a "dop" stick and polishing on water wheel stones and buffing. I used to do sample prep years ago as a grad intern at a national museum prep labs . Wed cut the mineral "thin sections" to 30 micron slabs that are glued onto a microscope slide with a type of souperglue or Canada Balsam. The optics of the microscopes use a series of polarizers and rotating fields of view. The colors that develop when light passes through the minerals at the 30 micron thickness transmits speciifc wavelenghths that are dependent upon the minerals composition. Its very cool and if youve been smoking some doobies the colors of minerals under a polarizing microscope are fantastic.