Glances

Article summary

Glance or glances ( ), sometimes also galenoids (similar to galena) — obsolete or partially obsolete collective name for the morphological group of minerals, compiled according to external characteristics. The group included more than three dozen names, mainly from the group of sulfides and related compounds. As a rule, different examples of glosses have a gray mirror or metallic luster with refractive indices above 3, and sometimes a metallike appearance. Unlike the related pyrites or blendes, glosses are not considered ″colored″ because they do not have the yellowish or reddish ″copper″ tones, although impurities may well give individual varieties shades of color. The group of glances was formed spontaneously by miners and mining practitioners, but mineralogy as a science recognized this group until the mid-twentieth century. However, even in the 17th-19th centuries, at a time when luster or pyrites were considered generally accepted scientific terms, mineralogists treated them without due categorical rigor, understanding them purely broadly as a morphological group united by external characteristics. For example, one of the most famous glances (iron) is not a sulfide, but an iron oxide.…

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