A. Can be scratched by a fingernail
Carnotite Yellow Bright canary 2
yellow or lemon
yellow;
radioactive;
occurs as crusts
and powdery masses
Gypsum White Yellowish; soft; 2
occurs as
crystals or as
fibrous,
granular, compact
or earthy masses
Limonite Rusty yellowish Brownish-yellow 1+
brown color; may be
soft and 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
Uranophane Light yellow to Yellow to 2-3
light yellow yellow-orange
orange color; radioactive
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
Calcite White Yellowish; dilute 3
hydrochloric acid
fizzes on
calcite; perfect
cleavage in 3
directions gives
rhomb-shaped
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
Uranophane Light yellow to Yellow to 2-3
light yellow yellow-orange
orange color; radioactive
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
Opal White Curved, 5-6
conchoidal
fracture; may
appear glassy,
greasy, resinous,
or dull
D. Cannot be scratched by an ordinary pocket knife but can be scratched
by quartz
Feldspar White Glassy or pearly 6
luster; good
cleavage in 2
directions that
meet at an angle
of 90° or near 90°
Garnet White Commonly occurs 6½-7
as crystals
Opal White Curved, 5-6
conchoidal
fracture; may
appear glassy,
greasy, resinous,
or dull
Quartz White Curved conchoidal 7
fracture;
brownish-yellow
_smoky_ quartz
crystals commonly
6-sided prisms
with pyramid-like
ends;
_chalcedony_ and
_jasper_ may be a
shade of yellow,
too