Gem and Showpiece

Gem noun - A usually valuable stone cut and polished for ornament.

Showpiece and gem are semantically related. In some cases you can use "Showpiece" instead a noun "Gem".

Showpiece noun - The outstanding item (the prize piece or main exhibit) in a collection.

Gem and showpiece are semantically related. Sometimes you can use "Gem" instead a noun "Showpiece".