Black Non-Nacreous Natural Pearls from Pteria sp.
The Bahrain Institute for Pearls & Gemstones (DANAT), Manama, recently received a 5.70 ct black pearl (9.49–9.51 ´ 8.75 mm) and an 11.84 ct black and brown pearl (13.63–13.71 ´ 9.55 mm), both of button shape (Figure 1). Viewed with the microscope,...
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