A. Can be scratched by a fingernail Gypsum White Brownish; soft; 2 occurs as crystals or as fibrous, granular, compact or earthy masses Limonite Rusty yellowish May be soft and 1+ brown earthy Muscovite (white White Light colored; 2-2½ mica) splits into thin, flat, transparent sheets that will bend without breaking Sulfur White or pale Will burn with a 1½-2½ yellow blue flame; commonly found as crystals, crusts, or grains B. Cannot be scratched by a fingernail but can be scratched by a copper penny Barite White Rather heavy; 3-3½ cleavage fragments may be flat and slab-like Biotite (black mica) White Dark brown; 2½-3 splits into thin, flat sheets that will bend without breaking Calcite White Dilute 3 hydrochloric acid fizzes on calcite; perfect cleavage in 3 directions gives rhomb-shaped fragments Halite White Salty taste; 2½ dissolves in water; cube-shaped cleavage fragments