BANDYLITE Meaning and
Definition
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Bandylite is a mineral belonging to the halide group, specifically to the carbonate-subgroup. It is categorized as a halide due to its composition containing chlorine as a key element. Bandylite is commonly found in hydrothermal Pb-Zn-deposits, occurring as primary or secondary mineralization. Its chemical formula is typically written as (Cu,Ag)_3(Cl,Br|I)2(B(O,OH)4), reflecting its composition that includes copper and silver along with chloride (Cl), bromide (Br), iodide (I), and borate (B(O,OH)4).
Physically, bandylite is characterized by its monoclinic crystal structure, which means it exhibits three unequal axes and one axis set oblique to the other three. This structure gives it a distinct symmetry and makes it easily identifiable by mineralogists. Bandylite usually appears as transparent to translucent, with individual crystals ranging in color from sky blue to deep blue-green. It can also occur as fine-grained rock masses or as an encrustation on other minerals within its host rock.
In geological terms, bandylite is considered a significant indicator mineral as its presence can provide vital clues about the evolution of ore deposits. Its occurrence and distribution assist geologists in understanding the geothermal processes involved in mineral formation. The name "bandylite" was derived from its discovery in the Bandya Mine, located near Durango, Colorado, USA, where it was first identified and described in 1893. Today, bandylite continues to be of interest to mineral collectors and researchers for its unique structure and its role in geological studies.
