specular iron technical
specularite technical

Iron mica - a very thin-leaved mica-like specularite - behaved differently depending on its genesis.

Specularite crystals in low-Mg calcite display crosscutting relationships with calcite and quartz indicating that calcite was primary, specularite secondary, and quartz tertiary.

One of the most interesting pieces is a discussion of spar boxes, a form of art naif or arte povera from the Pennines in which cabinets are turned into weird grottoes with local minerals: fluorspar, quartz, galena, hematite, specularite.