I don’t know what the design is, but I think your ring is Australian. ‘Apex’ was a trademark of G&E Rodd Pty Ltd, founded in Melbourne, Australia in 1919. Initially, George Rodd made ‘smallwork’ jewellery in gold and silver, was joined in partnership by his brother Ernest by 1922, and diversified to include fine tableware and then a whole host of other items. They merged with Myttons Ltd in 1961 and are still in production today as Mytton Rodd Ltd.
I would guess it’s from sometime between the mid-1920s-1950ish (probably excluding the WWII years). Australia has no official hallmarking system of a mandatory nature. The first attempts to introduce one came in 1916 and the first assay office opened in 1923 but: it wasn’t a country-wide scheme, was voluntary, industry-controlled, and short-lived. The Gold and Silversmiths Guild of Australia was formed in 1988 and a system of marking introduced (maker's mark, standard mark, guild mark and date letter) but it’s still a voluntary scheme with standards set by the industry for members of the Guild.
There's a good chance that a ring from an established maker like this will be 'as marked' 9ct gold. In other cases, it's going to be 'caveat emptor' (buyer beware), unless the format of the marks is from the standards operated by the Guild since 1988 and the maker is a member.