1900s Edwardian design, English. It was a period of considerable wealth for an increasing number of the population and the showing of that wealth, in fine dress, accoutrements, jewellery.
One of  the fine items people of standing used in this period was a pin for the neck cloths, tie pins to hold the cloth in place, the pin surmounted with an adornmment befitting the wearer. The solid Gold pendants in the above earrings are modelled directly on such a tie pin top, down to the bead-set Diamond within an eight-ray star.
Note that the Diamonds used in the above eardrops are of far higher quality, in terms of cut, colour and clarity, than the original Diamond, which was darkish, heavily included and unevenly facetted. Unfortunately, these original old cut, off-white Diamonds are very difficult to source in England, and virtually impossible to source in Australia.