A variety of Sphalerite

Compact, fine-grained Sphalerite of a mid-brown to yellow or cream color, occurring in concentric layers with reniform surfaces which also may contain intergrown, marcasite, pyrite, galena, and possible wurtzite. It is believed to have formed by relatively rapid crystallization of a low-temperature sulfide gel (gel: colloidal dispersion).

See “Best Minerals” article on Schalenblende, by Harjo Neutkens: https://www.mindat.org/a/best_schalenblende