One member of this group names a law that all members of the group follow, specifying that lamellar crystal twins are formed in stacks. That member, albite, falls with anorthite and oligoclase into one variety of this group, while the most prominent member of its other group is (*) orthoclase. It is classified around six on the Mohs scale, and all examples are aluminum-containing silicate minerals. For 10 points, name thi
One member of this group names a law that all members of the group follow, specifying that lamellar crystal twins are formed in stacks. That member, albite, falls with anorthite and oligoclase into one variety of this group, while the most prominent member of its other group is (*) orthoclase. It is classified around six on the Mohs scale, and all examples are aluminum-containing silicate minerals. For 10 points, name this group of minerals, classified into potassium and plagioclase varieties, the most abundant mineral group on Earth.
One member of this group names a law that all members of the group follow, specifying that lamellar crystal twins are formed in stacks.
feldspars