Gemma

Since my grandchildren couldn’t pronounce Grandma this was the name that sounded remotely close to what they were calling me! We, especially me, love It!

Allegedly also occasionally used in Hungary: https://hu.wikipedia.org/wiki/Gemma

Also Sicilian: https://scn.wikipedia.org/wiki/Noma_siciliani

Also means game in many different languages.

Also Polish: https://pl.wikipedia.org/wiki/Gemma_(imi%C4%99)
https://pl.wiktionary.org/wiki/Gemma

This name is also used in Catalan, where it is also the word for "gem". The data on the Instituto Nacional de Estadística website shows that it has been in use in Catalonia since before the 1930s (when the records began). [noted -ed]

Gemma was popular in Australia in the 80's and it's also spelt Jemma.

This name is also commonly used in The Netherlands. [noted -ed]

"Gemma" it is also a very common Catalan name and its meaning is from the same Catalan word 'Gemma', which means 'precious stone'. It's not a nickname but the word itself used nowadays for defining a precious stone.

Also Catalan.

Surprised to learn that this is a rare name in the States. It's fairly common in the UK.

Since the 1880's Gemma hasn't appeared on the top 1000 list.