Image: <bdi><a href="https://www.wikidata.org/wiki/Q126871366" class="extiw" title="d:Q126871366"><span title="photographer from the United States">Nessa Eull</span></a></bdi> (CC0)
monocliniccommonSilicates (Amphibole Group)
Hornblende
Ca2(Mg,Fe,Al)5(Al,Si)8O22(OH)2
Hornblende typically forms as black to dark green, prismatic to blocky crystals with a vitreous luster. In this specimen, it appears as black masses accompanying brown apatite and whitish calcite.
Hornblende Physical Properties
Mohs Hardness
5Crystal System
monoclinicLuster
vitreousStreak Color
white to grayish-whiteCleavage
Perfect prismatic on {110} at 56° and 124°Fracture
unevenSpecific Gravity
3.2Colors
black, dark green, dark brownTransparency
opaque to translucentType Locality
Quebec, CanadaMineral Group
Silicates (Amphibole Group)Uses
rock-forming mineral, scientific interestAssociated Minerals
apatite, calcite, quartz, feldspar, mica, pyroxeneRarity
commonGeological Context
Hornblende is a common rock-forming mineral found in various igneous rocks such as granite, diorite, gabbro, and basalt, as well as in metamorphic rocks like amphibolite, gneiss, and schist. It forms during the crystallization of magma or through the metamorphism of pre-existing rocks.
