These were purchased in an estate sale and had 2 unattractive orangish yellow cz stones set in these 14k yellow gold studs. I didn't think they were appropriate for the settings, so, using my metalsmith and stone setting skills, I swapped the cz stones out for these stunning 0.06ct moissanites (0.12ct TCW). These moissanites will test as diamond on a tester that cannot differentiate between moissy and diamond. The butterfly friction backings that were on here were not karat gold of any kind, so I replaced them with solid 14k yellow gold butterfly backings from my stock that were more appropriately sized for these studs. I'm assuming that the original 14k backs were lost and the ones I received them with were just a replacement.