Hello
In modern Greek "pearl" translates to "μαργαριτάρι".
I do not have specific knowledge of semi-precious or precious stones, but as far as I know "μαργαρῖται" or "μαργαριτάρι" does not have any other meaning, related to stones.
---------------------------------------------------------------------------------------------------------------------------
Vasiliki Baskou, Instructor/Director, https://learn-greek-online.com.