Mineral 2
Specimen dimensions: 4 x 2½ x ½ inches ( 100x65x15mm)
Specimen weight: 7⅛ ounces (205 grams)
Collection: Highland Campus
For reference: the U.S. penny is 0.75 inches [19.05 mm] in diameter.
Distinguishing Properties (click this to reveal) - make your list of observations before peeking
Distinguishing Physical Properties:
Note the Color: this is a dark, black to brownish colored mineral
Cleavage: the razer blade is a clue - this is what's called a platy mineral, you can peel off the layers in sheets, this means it has one "perfect" direction of cleavage
Appearance: perfect cleavage results in mineral peeling into thin, flexible sheets, sometimes thick specimens are called "books" because it looks like one could open the pages
what you can't tell from the photograph is the hardness, this mineral is soft, it can be scratched with a copper penny, perhaps even your fingernail