What is "gonnardite"

n. (context mineral English) A tetragonal-scalenohedral white mineral containing aluminum, calcium, hydrogen, oxygen, silicon, and sodium.

Gonnardite is a comparatively rare, fibrous zeolite, natrolite subgroup. Older papers claim that a complete solid solution exists between tetranatrolite and gonnardite, but tetranatrolite was discredited as a separate species in 1999. A series, based on the disorder of the silicon-aluminum in the framework, appears to exist between Na-rich gonnardite and natrolite, Na(SiAl)O·2HO.

Gonnardite was named in 1896 after Ferdinand Pierre Joseph Gonnard (1833–1923), who was Professor of Mining Engineering at the University of Lyon, France.