Answer: hornblende

AnswerCrossword Clue
HORNBLENDEAmphibole
HORNBLENDEAluminous mineral
HORNBLENDEGreen to black mineral
hornblendedark-green to black mineral of the amphibole group, calcium magnesium iron and hydroxyl aluminosilicate
hornblendethe common black, or dark green or brown, variety of amphibole