Search Mineralpedia – A Mineral Photo Database and Identification Guide

Named for the Greek word for “red,” erythros, in reference to the minerals common crimson color. Purple to reddish purple, crimson, pale rose, or pink, elongated tabular or knife-like crystals in the millimeter range to free-standing thick, tabular crystals to 1cm or more. Also in radial groups or stellate aggregates, can be fibrous, pulverulent, massive. Large crystals are rare and are easily seperated with a knife and are sectile showing a perfect cleavage. Occurs as a secondary mineral in the oxide zone of some Co–Ni–As-bearing mineral deposits such as Cobalt, Canada or Bou Azzer, Morocco. Common mineral with many other localities.

Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/erythrite.pdf

Professor Esper Signius Larsen Jr., former American petrologist and mineralogist at Harvard University in Massachusetts, USA, is the namesake of the mineral Esperite. Esperite is a rare mineral that occurs at its type locality in the Parker shaft of the Franklin mine in New Jersey, USA and at El Dragon mine in Potosi, Bolivia. At the type locality it occurs within the metamorphosed stratiform zinc orebody. Esperite has a bright yellow fluorescence under short-wave ultraviolet light and has a kelly green cathodoluminescence.

Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/esperite.pdf