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
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
C. Cannot be scratched by a copper penny but can be scratched by an
ordinary pocket knife
Barite White Rather heavy; 3-3½
cleavage
fragments may be
flat and slab-like
Dolomite White Commonly occurs 3½-4
as granular
masses and as
rhomb-shaped
crystals; dilute
hydrochloric acid
may fizz slightly
on dolomite
Fluorite White Cleavage in 4 4
directions can
give fragments
that are shaped
like octahedrons;
crystals commonly
cube-shaped
D. Cannot be scratched by an ordinary pocket knife but can be scratched
by quartz
Cassiterite Pale brown, pale Brown, reddish 6-7
yellow, or white brown, or
yellowish brown;
heavy; dull to
brilliant luster
Feldspar White Glassy or pearly 6
luster; good
cleavage in 2
directions that
meet at an angle
of 90° or near
90°; common in
granite and
pegmatite rocks
Garnet White Commonly occurs 6½-7
as crystals
Quartz White Curved conchoidal 7
fracture; brown
_smoky_ quartz
crystals commonly
6-sided prisms
with pyramid-like
ends;
_chalcedony_,
_chert_, and
_jasper_ may be a
shade brown, too
Tourmaline White Dark brown 7-7½
variety is
_dravite_; notice
hardness,
striations on
crystals, and
triangular cross
section of some
crystals
E. Cannot be scratched by quartz
Tourmaline White Dark brown 7-7½
variety is
_dravite_; notice
hardness,
striations on
crystals, and
triangular cross
section of some
crystals