Italian submarine Gemma was a Perla-class submarine built for the Royal Italian Navy during the 1930s. Her name in Italian means a gemstone or jewel.
Italian submarine Gemma
The Perla-class submarines were the third sub-class of the 600 Series of coastal submarines built for the Royal Italian Navy during the 1930s and named after gemstones. Of the ten boats built of this class, only three survived World War II.
Perla-class submarine (Perla)