Wiktionary
tschermakite
n. a complex silicate mineral (a kind of hornblende) containing calcium, magnesium, aluminium and ferric iron found in metamorphic rocks
Wikipedia
Tschermakite
The endmember hornblende tschermakite (☐Ca(MgAl)(SiAl)O(OH)) is a calcium rich monoclinic amphibole mineral. It is frequently synthesized along with its ternary solid solution series members tremolite and cummingtonite so that the thermodynamic properties of its assemblage can be applied to solving other solid solution series from a variety of amphibole minerals.