Appendix A: Reference Tables
Reference Tables
Properties of Some Common Minerals
In this table, minerals are arranged alphabetically, and the most useful properties for identification are
printed in italic type. Most minerals can be identified by means of two or three of the properties listed
below. For some minerals, density is important; for others, cleavage is characteristic; and for others, the
crystal shapes identify the minerals. The colors listed are the most common for each mineral.
Name
Hardness Color
Streak
Cleavage
Remarks
Apatite
5
Green, brown
White
5–6
Dark green
to black
Greenish
Poor in one
direction
Two directions,
nearly at 90°
7.5–8
Bluish-green,
yellow, pink,
colorless
White
Imperfect in
one direction
2.5–3
Black, brown,
dark green
White
Perfect in one
direction
3
White, colorless
White
3.5–4
Golden yellow
Greenish black
Perfect, three
directions, not
at 90° angles
Poor in one
direction
2–2.5
Greenish
Pale green to
gray or brown
Perfect in one
direction
Copper (Cu)
2.5–3
Copper red
Copper
None
Corundum
9
Brown, pink, blue
White
None, parting
resembles
cleavage
Diamond (C)
10
Colorless to
pale yellow
White
Perfect, four
directions
Dolomite
3.5–4
Pinkish, colorless,
white
White
Perfect, three
directions, not
at 90° angles
6
Salmon pink, red,
white, light gray
White
Good, two
directions, 90°
intersection
6
White to light
gray, can be
salmon pink
White
Good, two
directions,
about 90°
Fluorite (CaF2)
4
Varies
White
Perfect, four
directions
Galena (PbS)
2.5
Lead gray
Lead gray
Gold (Au)
2.5–3
Gold
Gold
Perfect, three
directions, at
90° angles
None
Graphite (C)
1–2
Dark gray
to black
Grayish black
Nonmetallic (glassy) luster.
Sp. gr. 3.1 to 3.2.
Nonmetallic (glassy) luster.
Stubby four-or eight-sided
crystals. Common type of
pyroxene. Sp. gr. 3.2 to 3.4.
Nonmetallic (glassy) luster.
Hardness, greenish color,
six-sided crystals. Aquamarine
and emerald are gem varieties.
Sp. gr. 2.6 to 2.8.
Nonmetallic (glassy) luster.
Thin elastic films peel off easily.
Sp. gr. 2.8 to 3.2.
Nonmetallic (glassy to dull)
luster. Fizzes in dilute
hydrochloric acid. Sp. gr. 2.7.
Metallic luster. Hardness
distinguishes from pyrite.
Sp. gr. 4.1 to 4.3.
Nonmetallic (glassy to pearly)
luster. Nonelastic flakes.
Sp. gr. 2.6 to 3.3.
Metallic luster on fresh surface.
Dense. Sp. gr. 8.9.
Nonmetallic (glassy to brilliant)
luster. Barrel-shaped,
six-sided crystals with flat ends.
Sp. gr. 4.0.
Nonmetallic (brilliant to greasy)
luster. Hardest of all minerals.
Sp. gr. 3.5.
Nonmetallic luster. Scratched
surface fizzes in dilute
hydrochloric acid. Cleavage
surfaces curved. Sp. gr. 2.8 to 2.9.
Nonmetallic (glassy) luster.
Hardness, color, and cleavage
taken together are diagnostic.
Sp. gr. 2.6.
Nonmetallic (glassy to pearly)
luster. If striations are visible,
they are diagnostic.
Sp. gr. 2.6 to 2.8.
Nonmetallic (glassy) luster. In
cubes or octahedrons as
crystals. Sp. gr. 3.2.
Metallic luster. Occurs as
crystals and masses. Dense.
Sp. gr. 7.4 to 7.6.
Metallic luster. Dense.
Sp. gr. 15.0 to 19.3.
Metallic or nonmetallic
(earthy) luster. Greasy feel,
marks paper. This is the “lead”
in a pencil (mixed with clay).
Sp. gr. 2.2.
(calcium fluorophosphate)
Augite
(complex silicate)
Beryl
(beryllium silicate)
Biotite mica
(complex silicate)
Calcite
(CaCO3)
Chalcopyrite
(CuFeS2)
Chlorite
(complex silicate)
(Al2O3)
(CaMg(CO3)2)
Feldspar
(Orthoclase)
(potassium aluminum silicate)
Feldspar
(Plagioclase)
(sodium and calcium
aluminum silicates)
Sp. gr. = specific gravity
700
Appendix A
Perfect in one
direction