The term "Hornblende" is an old German name for any dark, prismatic crystal found with metallic ores but containing no valuable metal (the word "Blende" indicates "a deceiver") [Herbert Bucksch, "Dictionary Geotechnical Engineering," 1995]
Alpine mountain, from German Matte "meadow, pastureland" (see mead (n.2)) + Horn (see horn (n.)). So called for its horn-like shape (cut by glaciers in the Ice Ages). The slopes are steep and treacherous; the Matte is for the meadows at its base. The Roman name was Mons Silvius, which might be based on a personal name.
"furnished with horn or horns," Old English hyrned, from source of horn (n.). The modern word probably is a new formation in Middle English. From late 14c. in reference to Moses, and the horn-like rays of light, symbols of power, that appeared on his head as he descended Mount Sinai. From 1620s in reference to cuckolds. Horned toad is from 1766; horned question is "a dilemma" (1540s).
The HORNED TOAD is frightful ; his head half the size of his body ; his jaws open enormously ; his eye lids have the form of a pointed cone, which makes them seem armed with horns, wherein are his eyes. His feet have something the air of hands. [Francis Fitzgerald, "The General Genteel Preceptor," 1747]