mineral Identification Flashcards
Dxic flow - 1st decision
Is its Luster: Non-metallic, or Metallic?
Color:
- non-metallic: Light or Dark?
- metallic: Streak’s color + mineral’s color
Second decision if
- Luster is non-metallic
- Luster is metallic
- Non-Metallic: Hardness vs. glass
- Metallic: Streak
If Non-Metallic, Light, is it:
- Harder than glass
- Softer than glass
Metallic - 3 groups of streak colors:
- Streak is black, gray, or greenish-black:
- Streak is brown to reddish-brown:
- Streak is yellow or brown:
Metallic - Streak is black, gray, or greenish-black, and: ✅1. Perfect cubic cleavage, silver-gray color: 2. Magnetic: 3. Steel gray color, H=1, greasy feel: 4. Golden yellow, greenish-black streak: 5. Brass yellow, cubic crystals:
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Galena - PbS
Metallic - 4th dxic criterion Streak is black, gray, or greenish-black, and: 1. Perfect cubic cleavage, silver-gray color: ✅2. Magnetic: 3. Steel gray color, H=1, greasy feel: 4. Golden yellow, greenish-black streak: 5. Brass yellow, cubic crystals:
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Magnetite - Fe₃O₄
Metallic - Streak is black, gray, or greenish-black, and: 1. Perfect cubic cleavage, silver-gray color: 2. Magnetic: ✅3. Steel gray color, H=1, greasy feel (not granular, fibrous, or micaceous [Hematite]): 4. Golden yellow, greenish-black streak: 5. Brass yellow, cubic crystals:
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Graphite - C
Metallic - 4th dxic criterion Streak is black, gray, or greenish-black, and: 1. Perfect cubic cleavage, silver-gray color: 2. Magnetic: 3. Steel gray color, H=1, greasy feel: ✅4. Golden yellow, greenish-black streak: 5. Brass yellow, cubic crystals:
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Chalcopyrite - CuFeS₂
Metallic - Streak is black, gray, or greenish-black, and: 1. Perfect cubic cleavage, silver-gray color: 2. Magnetic: 3. Steel gray color, H=1, greasy feel: 4. Golden yellow, greenish-black streak: ✅5. Brass yellow, cubic crystals:
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Pyrite - FeS₂
Metallic - Streak brown to reddish-brown, Mineral steel gray and granular, fibrous, or micaceous [not soft or greasy-feeling {≡Graphite}]
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Hematite - Fe₂O₃
Metallic - Streak yellow, brown, or brownish yellow; Mineral is yellow, brown, or black
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Limonite - Fe₂O₃•H₂O
If non-metallic, light, +H +Clvg, it is:
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Feldspar
Both types of feldspars exhibit good cleavage in 2 directions at 〜90º
Orthoclase - light to dark, salmon pinks (K)
Plagioclase - white, grays (Ca, Na)
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If it’s Non-met, +H (=7), —Clvg, +Conchoidal fracture it is:
Quartz - SiO2
A mineral is Non-Metallic, Light color, —H, ++Clvg has:
✅1. Perfect cubic cleavage; salty taste; colorless to white; soluble in water
- Perfect cleavage in 1 direction, poor in 2 others; H=2
- Perfect cleavage in 3 directions at 〜75°; effervesces in HCl / 4. efferv. only if powdered
- Good cleavage in 4 directions
- Perfect cleavage in 1 direction —> thin, elastic sheets
- Green to white; soapy feel; pearly luster; H=1; 1 dir of cleavage
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Halite - NaCl
A mineral is Non-Metall, Light color, —H, ++Clvg and has:
1. Perfect cubic cleavage; salty taste; colorless to white; soluble in water
✅2. Perfect cleavage in 1 direction, poor clvg in 2 others; H=2
3. Perfect cleavage in 3 directions at ~75°; effervesces in HCl / 4. efferv. only if powdered
5. Good cleavage in 4 directions
6. Perfect cleavage in 1 direction —> thin, elastic sheets
7. Green to white; soapy feel; pearly luster; H=1; 1 dir of cleavage
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Gypsum - CaSO4・2H2O
A mineral is Non-Metallic, Light color, —H, ++Clvg and has:
1. Perfect cubic cleavage; salty taste; colorless to white; soluble in water
2. Perfect cleavage in 1 direction, poor in 2 others; H=2
✅3. Perfect cleavage in 3 directions at ~75°; effervesces in HCl / or 4. efferv. only if powdered
5. Good cleavage in 4 directions
6. Perfect cleavage in 1 direction —> thin, elastic sheets
7. Green to white; soapy feel; pearly luster; H=1; 1 dir of cleavage
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Calcite - CaCo3
(Fine-grained crystaline aggregates form limestone and marble.)
A mineral is Non-Metallic, Light color, —H, ++Clvg and has:
- Perfect cubic cleavage; salty taste; colorless to white; soluble in water
- Perfect cleavage in 1 direction, poor in 2 others; H=2
- Perfect cleavage in 3 directions at ~75°; solid surface effervesces in HCl
✅4. Perfect cleavage in 3 directions at ~75°; effervesces in HCl only if powdered
- Good cleavage in 4 directions
- Perfect cleavage in 1 direction —> thin, elastic sheets
- Green to white; soapy feel; pearly luster; H=1; 1 dir of cleavage
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Dolomite - CaMg(CO3)2
A mineral is Non-Metallic, Light color, —H, ++Clvg and has:
1. Perfect cubic cleavage; salty taste; colorless to white; soluble in water
2. Perfect cleavage in 1 direction, poor in 2 others; H=2
3. Perfect cleavage in 3 directions at ~75°; effervesces in HCl / 4. efferv. only if powdered
✅5. Good cleavage in 4 directions
6. Perfect cleavage in 1 direction —> thin, elastic sheets
7. Green to white; soapy feel; pearly luster; H = 1; 1 dir of cleavage
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Fluorite - CaF2
A mineral is Non-Metallic, Light color, —H, ++Clvg and has:
1. Perfect cubic cleavage; salty taste; colorless to white; soluble in water
2. Perfect cleavage in 1 direction, poor in 2 others; H=2
3. Perfect cleavage in 3 directions at ~75°; effervesces in HCl / 4. efferv. only if powdered
5. Good cleavage in 4 directions
✅6. Perfect cleavage in 1 direction —> thin, elastic sheets
7. Green to white; soapy feel; pearly luster; H=1; 1 dir of cleavage
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Muskovite - KAl3AlSi3O10(OH)2
A mineral is Non-Metallic, Light color, —H, ++Clvg and has:
1. Perfect cubic cleavage; salty taste; colorless to white; soluble in water
2. Perfect cleavage in 1 direction, poor in 2 others; H=2
3. Perfect cleavage in 3 directions at ~75°; effervesces in HCl / 4. efferv. only if powdered
5. Good cleavage in 4 directions
6. Perfect cleavage in 1 direction —> thin, elastic sheets
✅7. Green to white; soapy feel; pearly luster; H=1; 1 dir of cleavage
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Talc - Mg3Si4O10(OH)2
A mineral is Non-Metallic, Light color, —H, —Clvg, with
Color: White to Red
Earthy masses
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Kaolinite - Al4Si4O10(OH)8
A mineral is Non-M, Dark, +H, +Clvg and has Cleavage in:
✅ 2 directions at nearly 90º; dark green to black;
2 directions at approx. 60º and 120º; dark green to black or brown;
Good cleavage in 2 directions at approx. 90º; gray to blue-gray;
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Pyroxene Group
Complex Ca, Mg, Fe, Al silicates
A mineral is Non-M, Dark, +H, +Clvg and has cleavage in:
2 directions at nearly 90º; dark green to black;
✅ 2 directions at approx. 60º and 120º; dark green to black or brown;
Good cleavage in 2 directions at approx. 90º; gray to blue-gray;
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Amphibole Group
Complex Na Ca Mg Fe Al silicates
A mineral is Non-M, Dark, +H, +Clvg and has Cleavage in:
2 directions at nearly 90º; dark green to black;
2 directions at approx. 60º and 120º; dark green to black or brown;
✅ Good cleavage in 2 directions at approx. 90º; gray to blue-gray;
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Plagioclase feldspar - NaAlSi3O8 to CaAl2Si2O4
A mineral is Non-M, Dark, +H, —Clvg and:
✅ 1. Comes in various shades of green; sometimes yellowish; commonly in aggregates of small, glassy grains;
- Is red, brown or yellow; vitreous luster;
- Conchoidal fracture; gray to gray-black; vitreous luster;
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Olivine - (Fe, Mg)2SiO4
A mineral is Non-M, Dark, +H, —Clvg and:
- Comes in various shades of green; sometimes yellowish; commonly in aggregates of small, glassy grains;
✅ 2. Is red, brown or yellow; vitreous luster;
- Conchoidal fracture; gray to gray-black; vitreous luster;
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Garnet Group - Fe, Mg, Ca, Al silicates
A mineral is Non-M, Dark, +H, —Clvg and:
- Comes in various shades of green; sometimes yellowish; commonly in aggregates of small, glassy grains;
- Is red, brown or yellow; glassy luster;
✅ 3. Conchoidal fracture; gray to gray-black; vitreous luster;
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Quartz - SiO2
A mineral is Non-M, Dark, -H, +Clvg and:
✅ 1. Brown to black; 1 perfect cleavage;
- Green to very dark green; 1 cleavage direction;
- Yellowish brown; resinous luster;
- Four perfect cleavage directions;
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Biotite - K(Mg, Fe)3AlSi3O10(OH)2
A mineral is Non-M, Dark, -H, +Clvg and:
- Brown to black; 1 perfect cleavage;
✅ 2. Green to very dark green; 1 cleavage direction; - Yellowish brown; resinous luster;
- Four perfect cleavage directions;
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Chlorite - Hydrous Mg, Fe, Al silicate
A mineral is Non-M, Dark, -H, +Clvg and:
1. Brown to black; 1 perfect cleavage;
2. Green to very dark green; 1 cleavage direction;
✅ 3. Yellowish brown; resinous luster; clvg in 6 directions;
4. Four perfect cleavage directions;
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Sphalerite - ZnS
A mineral is Non-M, Dark, -H, +Clvg and:
- Brown to black; 1 perfect cleavage;
- Green to very dark green; 1 cleavage direction;
- Yellowish brown; resinous luster;
✅ 4. Four perfect cleavage directions;
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Fluorite - CaF2
A mineral is Non-M, Dark, -H, -Clvg and:
✅ 1. Red, earthy appearance; red streak;
- Yellowish-brown streak; yellowish-brown to dark brown;
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Hematite - Fe2O3 (earth variety)
A mineral is Non-M, Dark, -H, -Clvg and:
1. Red, earthy appearance; red streak;
✅ 2. Yellowish-brown streak; mineral yellowish-brown to dark brown;
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Limonite - Fe2O3 • H2O