3.6: Mineral Appendix- Common Minerals and their Properties
- Page ID
- 14761
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Common Minerals and their Properties
Amphibole: Hardness value right around glass (~5.5-6); green to black, elongate, or rod-shaped crystals common; two cleavage directions not at 90°.
Augite: Hardness value right around glass (~5.5-6); blocky green to black crystals common; two cleavage directions at 90°.
Biotite: Dark colored mica mineral; sheet cleavage (1 direction); flexible.
Calcite: Reacts with HCl; rhombohedral shape and cleavage.
Corundum: hexagonal shape with flat ends; hardness of 9; many colors common, lab kits generally have dull, brown or purple varieties. If gem quality, red = ruby; blue = sapphire.
Dolomite: Reacts with HCl only when powdered; rhombohedral shape and cleavage.
Fluorite: Commonly cleaves in octahedral shapes. Hardness is less than glass, but greater than copper. Many colors are common.
Galena: High heft; cube-shaped crystals common; silvery-blue color.
Garnet: Typically dark red in color (although there are many varieties); may have hackly or uneven fracture; dodecahedron shape common.
Graphite: Soft, greasy feel; will leave marks on paper.
Gypsum: Soft, may be tabular or fibrous; transparent to opaque.
Halite: Cubic crystals common; waxy feel; taste is distinct.
Hematite: Brick-red streak; may be earthy or metallic in luster.
Hornblende: Hardness value right around glass (~5.5-6); green to black, elongate, or rod-shaped crystals common; two cleavage directions not at 90°.
Kaolinite: Soft, earthy, white; massive; sticks to tongue.
Kyanite: Blue color; bladed crystals; two different hardness values, H = 5, parallel to blade; H = 7 across blade.
Magnetite: Magnetic; metallic; harder than glass.
Muscovite: Colorless mica; sheet cleavage; transparent, flexible sheets.
Olivine: Green color; granular or sugary feeling masses.
Plagioclase feldspar var. Labradorite: Iridescent, dark gray; striations on cleavage faces; harder than glass.
Plagioclase feldspar var. Albite: White to grey; striations on cleavage faces; harder than glass.
Potassium feldspar: Commonly beige to pink or reddish, however Amazonite is blue-green; exsolution lamellae on cleavage faces; harder than glass.
Pyrite: Metallic, brassy gold, cubic shape common; green-black streak.
Pyroxene: Hardness value right around glass (~5.5-6); blocky green to black crystals common; two cleavage directions at 90°.
Quartz: Harder than glass; glassy look; crystal shape, hexagonal prismatic; many colors common.
Serpentine: Green, white, grey masses or fibrous. *Composes serpentinite, California’s state rock!
Sphalerite: Yellow to black submetallic, vitreous, or resinous crystals with 6 cleavage faces; can form dodecahedrons; smells like rotten eggs when scratched, powdered, or treated with acid. Softer than glass (H=3.5-4).
Sulfur: Yellow color and streak; light heft; brittle.
Talc: Soft, greasy feel; pearly or dull luster common.
Topaz: Harder than glass (H=8); adamantine luster, crystal shape, hexagonal prismatic; many colors common.
Tourmaline: Crystals are long, slender to thick prismatic and columnar with a triangular cross-section; crystal faces may be striated. Color is commonly brown to black in color (Schorl), however, the pink version, watermelon tourmaline, can be found near San Diego, CA!
Mineral Identification
Metallic and Submetallic Minerals
| Hardness | Cleavage | Streak | Characteristic Properties | Mineral Name |
|---|---|---|---|---|
|
Hard (H > 5.5) Scratches glass |
No cleavage or cleavage not visible | Dark gray/black | Brassy gold; cubic shape common; H 6-6.5 | Pyrite |
| Silvery dark gray to black; magnetic; H 6-6.5 | Magnetite | |||
| Hard or Soft | Red to brown | Steel gray to reddish silver; may be earthy or metallic in luster; H 5-6 | Hematite | |
|
Soft (H ≤ 5.5) Does not scratch glass |
Visible cleavage | Dark gray/black | Silvery-blue; high heft; cleaves into cubic crystals; H 2.5 | Galena |
| White to pale yellow | Silvery yellow-brown, red or black; submetallic to resinous luster; 6 cleavage planes; smells like rotten eggs when scratched or powdered; H 3.5-4 | Sphalerite | ||
| No cleavage or cleavage not visible | Dark gray/black | Dark silvery gray to black; soft, greasy feel; will leave marks on paper; H 1-2 | Graphite |
Dark to Medium-Colored Nonmetallic Minerals
| Hardness | Cleavage | Characteristic Properties | Mineral Name |
|---|---|---|---|
|
Hard (H > 5.5) Scratches glass |
Visible cleavage | Iridescent blue-gray (var. Labradorite); striations on cleavage faces; 2 cleavages at 90°; H 6 | Plagioclase feldspar |
| Commonly beige, tan, pink, orange, or blue-green; exsolution lamellae on cleavage faces; 2 good cleavages at 90°; H 6 | Potassium feldspar | ||
| Green to black; elongate or rod-shaped crystals common; 2 cleavages at about 124° and 56°; H 5.5-6 | Hornblende (an amphibole) | ||
| Blocky green to black crystals; dull to vitreous luster; 2 cleavages at nearly right angles; H 5.5-6 | Augite (a pyroxene) | ||
| No cleavage or cleavage not visible | Many colors common; vitreous luster; hexagonal prisms; transparent or translucent; H 7 | Quartz | |
| Many colors common; hexagonal shapes with flat ends; generally dull, brown or purple; gem quality may be red (ruby) or blue (sapphire); H 9 | Corundum | ||
| Brown to dark red in color; may have hackly or uneven fracture; dodecahedron crystal form; H 7 | Garnet | ||
| Brown to black but other colors common in California; long slender to thick prismatic crystals; crystal faces may be striated; H 7-7.5 | Tourmaline | ||
| Olive green; granular or sugary feeling masses; no cleavage; vitreous luster; H 7 | Olivine | ||
|
Soft (H ≤ 5.5) Does not scratch glass |
Visible cleavage | Yellow-brown to black; vitreous to resinous luster; smells like rotten eggs when scratched or powdered; H 3.5-4 | Sphalerite |
| Purple cubes or octahedrons; H 4 | Fluorite | ||
| Dark colored mica; splits easily along 1 cleavage face into thin, flexible sheets; H 2.5-3 | Biotite | ||
| No cleavage or cleavage not visible | Translucent or opaque dark green; soft, greasy feel; pearly or dull luster common; can easily be scratched with fingernail; H 1 | Talc | |
| Red to red-brown; may be earthy or metallic in luster; characteristic brick-red streak; H 5-6 | Hematite |
Light-Colored Nonmetallic Minerals
| Hardness | Cleavage | Characteristic Properties | Mineral Name |
|---|---|---|---|
|
Hard (H > 5.5) Scratches glass |
Visible cleavage | White to gray; striations on cleavage faces; 2 good cleavages at 90°; H 6 | Plagioclase feldspar |
| Commonly beige, tan, pink, orange, or blue-green; exsolution lamellae on cleavage faces; 2 good cleavages at 90°; H 6 | Potassium feldspar | ||
| Many colors common; adamantine luster; hexagonal prismatic shape; may display 1 perfect cleavage face; H 8 | Topaz | ||
| Blue; bladed crystals; H 5 parallel to blades; H 7 across blades | Kyanite | ||
| No cleavage or cleavage not visible | Many colors common; hexagonal shapes with flat ends; generally dull, brown or purple; gem quality may be red (ruby) or blue (sapphire); H 9 | Corundum | |
| Many colors common; vitreous luster; hexagonal prisms; transparent or translucent; H 7 | Quartz | ||
| Pale green to yellow color; granular or sugary feeling masses; no cleavage; vitreous luster; H 7 | Olivine | ||
|
Soft (H ≤ 5.5) Does not scratch glass |
Visible cleavage | Colorless, white, yellow, brown, green, pink; 3 excellent cleavages at 70°/110°; breaks into rhombohedrons; reacts with HCl; H 3 | Calcite |
| Colorless, white, gray, or pink; may display 3 excellent cleavages; effervesces only when powdered; H 3.5-4 | Dolomite | ||
| Transparent to opaque white or clear; may be tabular or fibrous; easily scratched with your fingernail; H 2 | Gypsum | ||
| Colorless to many colors; waxy feels; cubic crystals; salty taste; H 2.5 | Halite | ||
| Colorless, purple, blue, green, yellow; cleaves in octahedral shapes; H 4 | Fluorite | ||
| Colorless, yellow or brown mica; cleaves along 1 excellent cleavage into transparent, flexible sheets; H 2-2.5 | Muscovite | ||
| No cleavage or cleavage not visible | Yellow; smells like rotten eggs when powdered; brittle; light heft; H 1.5-2.5 | Sulfur | |
| Green, white, gray masses or fibrous; H 2.5-3.5 | Serpentine | ||
| Opaque white, gray, green, brown; soft, greasy feel; pearly or dull luster common; can easily be scratched with fingernail; H 1 | Talc | ||
| Soft, earthy, white; massive; sticks to tongue; powdery to greasy feel; H 1-2 | Kaolinite |