Yes, LIBRA is a Scrabble word!

Letter values in Scrabble US: L 1, I 1, B 3, R 1, A 1.

Is it a valid word?

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

(astrology) a person who is born while the sun is in Libra
a small faint zodiacal constellation in the southern hemisphere; between Virgo and Scorpius
the seventh sign of the zodiac; the sun is in this sign from about September 23 to October 22

Also: libra the balance, libra the scales.