When the molten mixture of glass and copper cools, the copper crystalises which creates the impression of a reddish-brown stone with a golden starry-glitter. The night-time constellation effect of goldstone lends it another of its alternate names: stellaria.
The reddish-brown hue of the stone is actually an illusion. The glass itself is transparent and is given the appearance of reddish-brown by the copper crystals.
There is some disagreement whether goldstone, due to its being synthetic, should be considered a gemstone. However, in common parlance, goldstone is referred to as a gemstone.
Goldstone has a Mohs hardness of 5.5 (comparable to the hardness of turquoise). It is often carved into jewellery and ornaments such as spheres or sitting Buddhas.
Goldstone can also be found in blue, which is paradoxically known as blue goldstone.
