Though I personally amn’t that keen on diamonds (I prefer dark stones, and ones without long ad campaigns trying to make the masses believe they’re the be-all and end-all of stones), there are many nice names meaning “diamond.” I’ve also included the words for diamond in other languages, where they sound enough like real names.
Unisex:
Almas is Arabic and Persian.
Dorji is Tibetan.
Kaimana is Hawaiian, and alternately means “ocean/sea power.”
Pich is Khmer.
Almaz is Amharic, Arabic, Ethiopian, Kazakh, Azeri, Kyrgyz, Tajik, Russian, and Ukrainian. It obviously is a very rare name in the two lattermost languages, probably not frequently used by native-born Russians and Ukrainians.
Daiya is Japanese. As with just about all other Japanese names, it can also mean many other things, depending upon the characters used, and which writing system.
Heera is Sanskrit, and also found in the various modern Indian languages.
Timantti is Finnish.
Yahalom is modern Hebrew.
Elmaz is Albanian and Bulgarian.
Male:
Almazbek means “diamond master” in Kyrgyz.
Diamant is Albanian.
Dimants is a rare Latvian name.
Sein is Burmese.
Tserendorj can mean “diamond longevity/long life” in Mongolian.
Watchara is Thai.
Xhevahir is Albanian. The letter XH is pronounced like the J in Jupiter.
Olmos is Uzbek.
Female:
Almast is Armenian.
Diamanto is Greek.
Intan is Malay and Indonesian.
Diamantea is Basque.
Adamantine means “diamond-like” in French.
Alimazi is Amharic.
Birlant means “like a diamond” in Chechen.
Deimantė is Lithuanian. It can also mean “intelligent goddess.”
Diamante is Judeo-Italian.
Gaukhar is Kazakh, and can also mean “precious, brilliant.”
Gewher is Kurdish.
Pharchara is Thai.
Almast is Armenian.
Almasi is Swahili.
Elmas is Turkish.
Onomastics Outside the Box 