The Mineral Identification Key Copper, Michigan, Seaman Museum specimen

Table IIA: Minerals with a Nonmetallic Luster, Definitely Colored Streak, and Hardness 1 to 6 [Previous Table [Next Table
Streak Hardness Color Cleavage Name System Habit SG Notes
Rust-red to Indian-red 1+ to 6½ Dark-brown to Steel-grey to Black   HEMATITE
Trigonal Usually massive in radiating, reniform, or micaceous aggregates  4.8 to 5.3 Hardness and S.G. lower in earthy massive materials, harder and denser in crystals and crystalline materials, crystals usually 5½ to 6½ with a metallic to sub-metallic luster
Pink 1½ to 2½ Pale-pink to Red Perfect in one direction ERYTHRITE
Monoclinic Usually as earthy crusts or powdery coatings on cobalt minerals, may be reniform 2.95 Streak same color as the sample but paler. Rare. (See also annabergite, below.)
Pale-pink to Light-green 1½ to 2½ Apple-green , Grey, Pale-rose Perfect in one direction ANNABERGITE
Monoclinic Usually as coatings or crusts of tiny crystals, grainy-appearing, crystals bladed  3.0 to 3.23 Streak same color as sample but lighter; Rare.  (See also erythrite above.)
Red 2 Red   LITHARGE
Tetragonal As alteration crusts on massicot (see below) 9.14 Rare
Streak Hardness Color Cleavage Name System Habit SG Notes
Bright-Scarlet-red or Vermilion to Brownish-red 2 to 2½ Dark Ruby-
red or Bright Ruby-red
One distinct direction PROUSTITE/
Trigonal Prismatic, pyramidal, rhombohedral, and scalenohedral crystals , also massive, usually as complex intergrown crystal aggregates 5.58 (pyrargyrite)
5.57 (proustite)
Isostructural species difficult to distinguish, though pyrargyrite is usually darker in color and more common than proustite, fusible in candle flame. Rare.
Dark-red Dark-red to Vermilion One perfect direction CINNABAR
Trigonal Usually earthy or granular, commonly impure and dark red or reddish-brown, bright-red and translucent to transparent when pure, crystals rhombohedral or tabular to short prismatic 8.10 Luster of crystals adamantine, may appear sub-metallic, heavy
Bright- to Deep-red 2½ to 3 Orange-yellow One distinct direction CROCOITE
Monoclinic Usually in prismatic crystals with an adamantine to sub-vitreous luster, as parallel to jackstraw clusters, may be hollow 5.9 to 6.1 Decrepitates (crumbles explosively) in a candle flame
Dark-red 3½ to 4 Ruby-red to Reddish-brown   CUPRITE
Isometric Usually in octahedral or cubic crystals, may be in slender crystals, may also be massive 6.0  
Streak Hardness Color Cleavage Name System Habit SG Notes
Orange-or Reddish-yellow 1½ to 2 Dark-red One good direction REALGAR
Monoclinic Usually massive, granular, coarse to fine, and as crusts 3.48 Luster resinous, easily fusible in a candle flame; usually associated with Orpiment
Orange-yellow 4 to 4½ Yellow to
Orange-yellow to Deep-red
perfect direction
Hexagonal Usually massive as irregular grains or rounded masses 5.64 to 5.68 Luster sub-adamantine to sub-vitreous, fluoresces green to yellowish-green under long wave ultraviolet light. Rare outside of Franklin, N.J., USA.
Pale-yellow 1½ to 2½ Lemon-yellow One perfect direction
giving thin plates
Monoclinic Usually in foliated masses or grains 3.49 Flexible, luster resinous, pearly on cleavage surfaces, easily fusible in a candle flame, usually associated with Realgar
Pale-yellow 1½ to 2½ Bright-yellow Imperfect  in three directions SULFUR
Orthorhombic Usually imperfectly crystallized masses or crusts 2.05 to 2.09 Resinous to sub-vitreous luster, may appear somewhat earthy when massive or as crusts, readily burns in a candle flame giving a blue flame.
Pale-yellow 2 Sulfur-yellow   MASSICOT
Orthorhombic Usually earthy or scaly masses 9.56 Usually replaces other Pb minerals, particularly galena, scales flexible.  Rather rare.
Streak Hardness Color Cleavage Name System Habit SG Notes
Very Pale-yellow to Yellowish-green 2 to 2½ Lemon-yellow to Greenish-yellow One perfect direction and one distinct direction AUTUNITE/
Usually as micaceous or scaly foliated aggregates, crystals thin or thick tabular 3.15 (autunite), 3.44 (meta-autunite) Luster vitreous to adamantine, fluoresces bright greenish-yellow. (See also torbernite/metatorbernite below, does not fluoresce.) Naturally occurring material is almost invariably meta-autunite
Very Pale-yellow, Yellowish-white (both rarely seen), White 2½ to 3 Orange-red to Ruby-red, Brownish-red to Brownish-yellow or Pale Straw-yellow   VANADINITE 
(Apatite Group)

Hexagonal Usually in barrel-shaped prismatic hexagonal crystals, either long or short, may be acicular in clusters or mats ("endlichite"), and as hollow prisms– "hopper" crystals 6.88 Luster sub-vitreous to sub-resinous
Very Pale-green 2 to 2½ Emerald- to Grass-green, Apple-green, Leek-green One perfect direction and one indistinct direction TORBERNITE/ METATORBERNITE
Tetragonal Usually as micaceous or scaly foliated aggregates, crystals thin to thick tabular 3.22
(torbernite), 3.70 (metatorbernite)
Luster vitreous to adamantine, similar to autunite/meta-autunite but truly green and does not fluoresce like autunite/meta-autunite. (See also autunite/ meta-autunite above.) Naturally occurring material is almost always metatorbernite
Light-green 3 to
Dark to Bright Emerald-green One perfect direction, a second fair direction ATACAMITE
Orthorhombic Usually in granular cleavable masses, crystals prismatic and usually very small to microscopic 3.75 to 3.77 Fusible in a candle flame. Rare.
Streak Hardness Color Cleavage Name System Habit SG Notes
Light-green Dark Emerald-green One perfect direction, one poor direction ANTLERITE
Orthorhombic Usually as mats of tiny acicular crystals, may be granular 3.88 Vitreous luster, may appear sub-vitreous or dull in mats. Rare.
Light-green 3½ to 4 Dark Emerald-green to Bright-green   BROCHANTITE
Monoclinic Usually as crusts or mats of tiny crystals, crystals may be stout prismatic to acicular or tabular 3.97 Vitreous luster
Light-green 3½ to 4 Dark- to Bright-green One perfect direction MALACHITE
Monoclinic As either radiating fibrous masses, botryoidal to mammillary, or as slender to stout prismatic crystals, often poorly formed (and often psuedomorphic after azurite), may be crusts, or acicular stellate sprays 3.9 to 4.03 Luster adamantine to vitreous, may appear sub-vitreous to dull on surfaces of masses. Often associated with azurite
Pale Bluish-white to White or Colorless 1½ to 2 Deep-blue or Deep Greenish-blue to Bluish green One perfect direction VIVIANITE
Monoclinic Usually as flattened to bladed prismatic crystals, often in stellate clusters or sprays, may also be granular, crusts, or reniform masses 2.68 Streak: darkens to Dark-blue or Brown after exposure, vitreous luster. Rare
Very Pale-blue to Grey or Tan 2 to 4 Pale- to Deep-blue, Blue-green, Green   CHRYSOCOLLA
  Usually in glassy, opaline, or porcellaneous masses or crusts, often as mats of very fine acicular crystals, may be botryoidal 1.93 to 2.40 Luster may be vitreous, waxy, porcellaneous, or dull.
Streak Hardness Color Cleavage Name System Habit SG Notes
Light-blue Azure-blue to Bright-blue   LINARITE
Monoclinic Usually as clusters or sprays of tiny elongated prismatic or tabular crystals, bladed, may also be in crusts of crudely formed crystals 5.35 Luster vitreous to sub-adamantine, easily fusible in a candle flame
Light-blue 3½ to 4 Deep Azure-blue One perfect direction AZURITE
Monoclinic Usually as small stout prismatic crystals, may be in sprays or radiating spherical groups 3.77 Luster vitreous, may appear sub-vitreous to dull on surfaces of radiating spherical masses;  usually associated with malachite
Bright-blue 5 to 5½ Deep-blue to Medium-blue and Violet-blue One distinct direction LAZURITE
Isometric Usually massive, compact to granular, crystals rare, dodecahedral 2.38 to 2.45 Luster vitreous in crystals, dull in massive material. Rare. Principal mineral found in the gem stone Lapis Lazuli
Very Pale-blue to White 5½ to 6 Light- to Medium-blue, Violet-blue,
Grey, or White
One poor to distinct direction SODALITE
Isometric Usually massive granular, crystals rare, dodecahedral, octahedral. Rare 2.14 to 2.30 Luster vitreous in crystals to dull in massive material, may fluoresce orange to orange-red
Streak Hardness Color Cleavage Name System Habit SG Notes
Brown 3½ to 4 Light-tan to Dark-brown Perfect  in three directions producing rhombic fragments SIDERITE
Trigonal Usually in cleavable masses, crystals usually rhombohedrons, faces curved 3.83 to 3.88 Becomes magnetic when heated in a candle flame
Brown 3½ to 4 Dark-brown to Black One perfect direction FERBERITE/
("Wolframite" series)

Monoclinic Usually massive, granular, crystals tabular to bladed with vertical striations 7.0 to 7.5
S.G. above 7.3 indicates ferberite, lower indicates hübnerite
Color black in ferberite, brown in hübnerite. Streak darkens with increasing Fe content
Light-brown 3½ to 4 Dark to Light-brown, Olive-brown, Reddish brown, Reddish-black Perfect in six directions SPHALERITE
Isometric Usually in cleavable masses, granular, crystals blocky wedge-shaped 3.9 to 4.1 May have an oily, submetallic, luster, streak usually lighter than the specimen
Streak Hardness Color Cleavage Name System Habit SG Notes
Yellow-brown to Ocher-yellow 5 to 5½ Dark-brown to Black One perfect direction GOETHITE (pronounced "Ger-ta-ite")
Orthorhombic Usually in reniform or radiating fibrous masses, botryoidal or mammillary, also stalactic 4.4 Luster usually dull, may be submetallic.
Light-brown 6 to 6½ Reddish-brown to Black One distinct direction RUTILE


Tetragonal Usually in slender prismatic crystals with vertically striated faces, as "elbow twins" (reticulated) and "sixlings" 4.18 to 4.25 Luster adamantine, may appear submetallic, usually translucent
Brown to Black 6 to 7 Light-brown to Greyish or White One imperfect direction CASSITERITE
Tetragonal Usually as fibrous, reniform, or irregular masses, stream-worn nuggets, with a dull to submetallic luster, crystals usually twined, with a submetallic or adamantine luster 6.8 to 7.1 Streak usually lighter than the specimen

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