Hornblende
Hornblende is a silicate mineral recognized among collectors for its crystal form and distribution, with several world-class Chinese localities.
About Hornblende
Hornblende is classified as a silicate mineral in the amphibole group — calcic amphiboles and has the chemical formula (Ca,Na)2-3(Mg,Fe,Al)5(Al,Si)8O22(OH)2. It crystallizes in the monoclinic system and holds a steady position among silicate species. Its combination of structural character and global distribution make it a recognized species in both systematic and aesthetic collections.
Identification & care
Specimens usually show prismatic, elongated, bladed, massive, columnar. Its color is typically black, dark green and dark brown. The luster is vitreous to silky, the streak is white to gray, and specimens range from translucent to opaque. The cleavage is perfect {110} at 56° and 124° (diagnostic amphibole cleavage angle). The fracture is uneven, which aids identification.
Collector context
How it forms
The geological setting for Hornblende is typically primary mineral in intermediate and mafic igneous rocks (diorite, andesite, gabbro, basalt); metamorphic amphibolites and hornblende schists. It is commonly found in association with plagioclase, augite, biotite, quartz, magnetite.
Classic Chinese localities
**Huanggang Fe-Sn deposit** is an important Chinese source for the species.
Why collectors care
Hornblende is a frequently-sought species in serious collections because its habit is recognizable, its color often strong, and its best examples unmistakable even at a distance. Chinese material has driven much of the recent visual shift in the species — sharper crystals, deeper colors, cleaner matrix.
What affects value
Value in Hornblende is assessed, in typical order of weight, against: (1) locality provenance; (2) size relative to the species norm; (3) crystal form and termination sharpness; (4) color saturation and zoning; (5) transparency and internal clarity; (6) matrix quality and aesthetic balance; (7) condition (absence of damage, chips, or repair). Cleaning quality and verified locality documentation act as multipliers across the above.
Naming history
The name Hornblende has a specific etymological and historical context — see Mindat's reference entry for provenance details. We have retained naming data at the record level; published prose is paraphrased from factual fields rather than copied from source.