Any images of the shell it came from or any idea on its history/provenance? Although interesting it is rather hard to decide whether it is a "blister pearl", "blister" or a piece of large worked and polished Tridacna gigas shell?
It was found in Sulu sea philippines. An expert who tested the actual giant pearl said that it cost about $450,000 or above. It is a natural pearl from giant clam. It is definitely a Tridacna pearl
If authentic it has no gem value. Museum value perhaps, but not high. This piece presents with numerous concerns, no less complete absence of time, date and location of harvest. No images in situ nor adequate documentation supporting licensed harvest, trade or possession. Undocumented, trade in tridacna parts is otherwise illegal in most countries.
Similar pieces have been posted here before and almost all are cut from shells. When that occurs, the object is considered destroyed. In that scenario, the only value add was the intact shell.
