Gemme
From LSJ
Τοὺς δούλους ἔταξεν ὡρισμένου νομίσματος ὁμιλεῖν ταῖς θεραπαινίσιν → He arranged for his male slaves to have sex with female slaves at a fixed price (Plutarch, Life of Cato the Elder 21.2)
Gemme, gemma. – Gemmenhändler, gemmarius (Inscr.). – Gemmenschneider, gemmarum scalptor.