General term for cut and polished precious or semi-precious stones used in jewelry or decoration.
She received a jewel ring for her birthday.
This gem is very expensive.
She always wears a small gem on her.
The gem on the ring sparkled in the light.
A large gem was set into the ring.
An expert appraised this gem.
宝石 is the standard word for a gem or jewel, whereas ストーン is often used more casually for decorative gemstones, especially in fashion or nail art.
宝石 is the standard word for a cut gemstone or jewel, whereas 石 alone can mean a precious stone but is much less specific.
jewelry box; jewel case
artificial jewels; synthetic gems