feldspar: any of a group of hard crystalline minerals that consist of aluminum silicates of potassium or sodium or calcium or barium
spar: any of various nonmetallic minerals (calcite or feldspar) that are light in color and transparent or translucent and cleavable
beta-interferon: a form of interferon that is produced by fibroblasts and have antiviral effects; used in the treatment of multiple sclerosis