This is a Heavy Quality Retro 14 Carat Yellow Gold and Natural Multicolour Opal Bar Brooch, probably from the mines at Coober Pedy in Australia.
This brooch is made to the highest standards and would not be a massed produced piece of jewellery, but designer made.
It is a quality opal which is high domed, 14mm by 11mm and of approx. 4.00 carats. It has a grey background colour with bright flashes of red, turquoise, yellow, green and blue across its entire surface.
The overall dimensions of the brooch itself are 66mm long, 13mm high, 10mm deep and it weighs a hefty 10.45 grams.
The piece is stamped “585”, which is a German mark for solid 14 carat gold, together with a maker’s mark which resembles a clock face at 3pm.
Difficult to date precisely, but I think Circa 1960’s or thereabouts.
It has been polished/sonically cleaned and is in excellent overall condition, with no damage/repair or obvious signs of wear.
A beautiful and totally unique quality gold brooch for those who like something different and exclusive in their jewellery.