Yes, ETNA is a Scrabble word!

Letter values in Scrabble US: E 1, T 1, N 1, A 1.

Is it a valid word?

ETNA is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

an inactive volcano in Sicily; last erupted in 1961; the highest volcano in Europe (10,500 feet)
a gas burner used in laboratories; has an air valve to regulate the mixture of gas and air

Also: mount etna, mt etna, bunsen burner.

Not playable in Scrabble US: BUNSEN.