chloropal

English

Etymology

From chloro- +‎ opal.

Noun

chloropal (plural chloropals)

1. (mineralogy) A massive mineral, greenish in colour and opal-like in appearance, essentially a hydrous silicate of iron.
   • 1877, J. H. Collins, “Remarks on Gramenite from Smallacombe, and on the Chloropal Group of Minerals”, in The Mineralogical Magazine and Journal of the Mineralogical Society‎^[1], page 70:

     A careful consideration of the various analyses of minerals of the chloropal group given by Dana, leads me, therefore, to propose that the following species and varieties should be regarded as a series of types to which all future discoveries in the group may be referred.

   • 1905, B. K. Emerson, “Plumose diabase and palagonite from the Holyoke trap sheet”, in Bulletin of the Geological Society of America‎^[2], volume 16, page 105:

     Several delessites and chloropals occurring in basalts have a composition very close to that of the glass.

   • 1969, T. R. Meyers, The Geology of New Hampshire: Minerals and mines, page 18:

     Nontronite, a variety of chloropal occurs as a light yellow powder in druses of the North Conway granite (99, p. 312).

Further reading

• David Barthelmy (1997–2024) “Chloropal”, in Webmineral Mineralogy Database.