Arcubisite (Ag6CuBiS4) is a sulfosalt mineral occurring with cryolite in Greenland. It is named after its composition (ARgentum, CUprum, and BISmuth). Its IMA symbol is Acb.
References
Mindat.org - Arcubisite Webmineral - Arcubisite Handbook of Mineralogy - Arcubisite nice2have.info handmade (in German)