Breccia with glassy grains of massive willemite. The blue mineral is magnesioriebeckite. A well-known secondary breccia assemblage from Franklin. Willemite in this assemblage is uncommon, but where found it is, in some specimens, colored blue by included magnesioriebeckite. Such specimens are highly prized by collectors. The origin of this breccia has not yet been determined. The magnesioriebeckite in old collections is commonly labeled “crocidolite.”