Muscovite

Muscovite is a natural potassium-aluminium mica, KAl₂(AlSi₃O₁₀)(OH)₂, and the most common member of the mica group. Pure thin sheets are colorless to silvery white, but impurities tint it; Mindat notes that pink to red muscovite can owe its color to manganese (Mn³⁺) rather than lithium. The dark pink to red-brown beads sold as "muscovite" in the crystal trade are described by the Japanese retailer Pascle as manganese-colored muscovite, which is consistent with this, although no laboratory test of those beads was found.