Blue gold

The intermetallic compound formed between gold and indium, AuIn2, gives rise to a clear blue colour and that between gold and gallium, AuGa2, to a bluish hue. The reflectivity curves for these 2 intermetallic compounds are also published in the paper by Saeger & Rodies in Gold Bulletin and the Cielab colour co-ordinates for AuIn2 by Agarwal & Raykhtsaum in Proc. Santa Fe Symposium.
AuIn2 (46% gold) and AuGa2 (58.5% gold) have melting points of 540.7°C and 491.3°C respectively. Off-stoichiometric compositions, like purple gold, will be 2 phase and so can be expected to have some measure of workability and toughness.Manufacturing techniques will also be similar to those for purple gold.