Australian 9 carat gold hallmark.

by Shelly
(N.S.W. Australia)

Hi, I recently bought a 9 carat gold and opal ring, and the seller told me that the hallmark suggests that it was made in Australia around 1900s. It is a handmade piece without a maker's mark. The hallmark is 9 Ct , the small t is underlined. Is this a old style of 9 carat hallmarking? Thanks.