precious stone
US /ˈpreʃ.əs stoʊn/
UK /ˈpreʃ.əs stoʊn/

1.
pietra preziosa, gemma
a valuable mineral or rock, such as a diamond, ruby, or emerald, used in jewelry and for other ornamental purposes
:
•
The crown was adorned with many beautiful precious stones.
La corona era adornata con molte belle pietre preziose.
•
She inherited a necklace with a rare precious stone.
Ha ereditato una collana con una rara pietra preziosa.