A. Will leave mark on paper Argentite Shiny, blackish Lead-gray color 2-2½ to lead grey that tarnishes to dull black; knife cuts it smoothly; heavy; may occur as masses and coatings Graphite Black Greasy feel; very 1-2 soft; splits into thin flakes Pyrolusite Black Very soft; will 1-2 soil fingers; may be powdery B. Does not readily leave mark on paper but can be scratched by an ordinary pocket knife Chalcocite Grayish black Shiny lead-gray 2½-3 color that tarnishes to dull black; knife cuts it smoothly; may have a black sooty coating; commonly occurs as compact or granular masses Hollandite Black May occur as 4-6 rounded masses Limonite Rusty, yellowish Some specimens 5-5½ brown have shiny black surface; notice streak C. Cannot be scratched by an ordinary pocket knife Braunite Steel gray or Luster is 6-6½ black submetallic Cassiterite Pale brown, pale Submetallic 6-7 yellow, or white luster; heavy; notice streak Hematite Dark reddish brown Notice streak; 5½-6½ commonly occurs (may be as granular or softer) compact masses Hollandite Black May occur as 4-6 rounded masses