troctolite
Concise Oxford English Dictionary © 2008 Oxford University Press:
troctolite /ˈtrɒktə(ʊ)lʌɪt/
▶noun Geology a form of gabbro (rock) typically having a spotted appearance likened to a trout's back.
– origin C19: from Ger. Troklotit, from Gk trōktēs, a marine fish (taken to be ‘trout’).
'troctolite' also found in these Oxford entries:

