Here's one of the specimens in my collection. It has exceptionally large clear calcites with deep amber color. If you are looking for a good specimen, try to find one with an unbroken arch and large, undamaged calcite crystals with good color. There are a lot of specimens out there, but it is so easy to damage either the calcite or the clam while you are collecting that a perfect specimen is clearly worth more. By the way, I did not break open this clamshell to reveal the calcite...this is the way these specimens are found. The shell has partially dissolved away and maybe the very same calcium carbonate that used to be in the shell has been re-deposited as calcite crystals. At any rate, you could not ask for a more beautiful fossil - mineral combination! Thanks Eddie!