Hi Sandro, Thank you for posting this as it made me think about this black coral tiger which looks similar to yours, I bought in Thailand, and forgot that I had. This one has "Khon" (Thai religious) script incised on it which makes it an amulet of some sort. For a long time I thought it may be copy because it was so light in weight, but I just googled it and came up with the link below and found out this was one of the hallmarks of authentic black coral BTW some black corals can live 4500 years in their colonial form.