Calcite

3-D, non-90° (Rhombohedral)

HCl reaction

Non-Metallic, Light and Soft

Hardness, 3.0

SG 2.7

transparent to opaque

Dolomite

3-D, non-90° (rhombohedral)

powder reacts with HCl

Non-Metallic, light & soft

Hardness 3.5-4.0

Commonly white-pink

powder effervesces in HCL

Cleavage is difficult to determine

Augite

2-D, 90°

(Prismatic 90°)

Dark Green to Black

Don't confuse with Horneblende

Non-Metallic, Dark & Hard

Hardness 6.0

SG 3.5

Biotite

1-D

Pinacoidal cleavage

 thin elastic sheets

Non-Metallic

Chalcopyrite

fracture

Metallic

Golden Yellow on fresh surfaces

Hardness 4

SG 4.3

Usually massive, tetragonal crystals rare

Tourmaline

Elongate crystals with trigonal cross-sect

No Cleavage

Non-Metallic

Hardness, 7.5

SG 3.0-3.2

Crystal faces vertically striated

usually black, brown, pink and green

Talc

1-D, Pinacoidal

Soapy Feel

Very soft, Hardness 1.0

SC 2.8

Pearly Luster

White or green

Sphalerite

6-D cleavage, dodecahedral

Metallic Luster

Yellowish brown; resinous to submetallic luster

Hardness 3.5-4.0

SG 4.0

Yellowish streak

Serpentine

1-D, Pinacoidal

shades of green (rarely yellowish or black)

waxy or fibrous luster (two forms)

Hardness 3.0-5.0

SG 2.5

Quartz

conchoidal fracture; vitreous

Hardness 7.0 (will scratch glass)

SG 2.65

Transparent or Translucent

Hexagonal crystals capped with pyramids

no cleavage

Pyrite "Fools Gold"

Metallic

fracture

Brass yellow

lacks cleavage

Hardness 6.0-6.5

SG 5

cubic crystals

granular aggregates are common

Plagioclase

2-D cleavage, 90°

Prismatic 90°

Hardness 6.0-6.5

SG 2.5

White or tan + dark colors

Striations on cleavage surface

occasional bluish irridescence

Orthoclase

2-D cleavage, 90°(at right angles)

Prismatic 90°

Hardenss 6.0-6.5

SG 2.5

White, Pink, Tan and Dark Colors

No Striations on Cleavage surface

no irridescence

Olivine

fracture

Olive-Yellowish Green

Commonly granular

Hardness 6.0-6.5

SG 3.5-4.5

Glassy Luster

Transparent to transluscent

Muscovite

1-D

Pinacoidal Cleavage

thin eleastic sheets

White or silvery in thick masses

Hardness 2.0-3.0

SG 2.8

Limonite

fracture

Earthy masses

Yellowish brown to orange streak is diagnositc

Hardness and SG vary

yellowish brown to dark brown

Kaolinite

looks like chalk

No HCL reaction

1-D but too small to see.

earthy luster and odor

Very soft

White or red in color

Becomes plastic or sticky when moistened

Horneblende

2-D cleavage, non-90°

prismatic non-90°

Hardness 6.0

SG 3.0-3.5

Dark Green to Black

Often shiny

Hematite

fracture

Red color, reddish brown streak (diagnostic)

Hardness varies

earthy to metallic luster

has a red dust

Halite

3-D, 90°

cubic cleavage

Salty taste

greasy feel

Soft, Hardness 2.0-2.5

SG 2.0

Colorless, white, transparent

Gypsum

3-D, 90° and non-90°

no-name or combo

Soft, Hardness 2.0

SG 2.3

White, Transparent to Translucent

Garnet

conchoidal fracture

no cleavage

red to dark brown

vitreous to dull

non-metallic

Very Hard 7.0-7.5

SG 3.5-4.5

Spherical 12,24,36 sided crystals

Galena

3-D, 90°

Cubic

Metallic

Heavy, SG 7.6

Hardness 2.5

Silvery Gray, shiny

Fluorite

4-D

Octahedral cleavage

Soft, Hardness 4.0

SG 3.0

Colorless, yellow, green, or violet

cubic crystals; transparent

looks like broken colored glass

Corundum

fracture

Hexagonal barrel shaped (flat topped and bottomed crystals)

Very Hard, 9.0 hardness

SG 4.0

Allochromatic: red=ruby, blue=sapphire, gray, brown etc.

Chlorite

1-D

Pinacoidal cleavage

Soft, 2.0-2.5 hardness

SG 2.5-3.5

Green to dark green

flexible, non-elastic

look for small flakes

Chalcopyrite

fracture

Metallic

Golden Yellow on fresh surfaces

Hardness 4

SG 4.3

Usually massive, tetragonal crystals rare

Talc

1-D, Pinacoidal

Soapy Feel

Very soft, Hardness 1.0

SC 2.8

Pearly Luster

White or green

Calcite

3-D, non-90° (Rhombohedral)

HCl reaction

Non-Metallic, Light and Soft

Hardness, 3.0

SG 2.7

transparent to opaque

Dolomite

3-D, non-90° (rhombohedral)

powder reacts with HCl

Non-Metallic, light & soft

Hardness 3.5-4.0

Commonly white-pink

powder effervesces in HCL

Cleavage is difficult to determine

Biotite

1-D

Pinacoidal cleavage

 thin elastic sheets

Non-Metallic

Chalcopyrite

fracture

Metallic

Golden Yellow on fresh surfaces

Hardness 4

SG 4.3

Usually massive, tetragonal crystals rare

Chlorite

1-D

Pinacoidal cleavage

Soft, 2.0-2.5 hardness

SG 2.5-3.5

Green to dark green

flexible, non-elastic

look for small flakes

Copper

hackly fracture

Red on fresh surfaces; dull tarnish

Soft and malleable

reddish streak color

High SG 8.9, heavy

Corundum

fracture

Hexagonal barrel shaped (flat topped and bottomed crystals)

Very Hard, 9.0 hardness

SG 4.0

Allochromatic: red=ruby, blue=sapphire, gray, brown etc.

Dolomite

3-D, non-90° (rhombohedral)

powder reacts with HCl

Non-Metallic, light & soft

Hardness 3.5-4.0

Commonly white-pink

powder effervesces in HCL

Cleavage is difficult to determine

Fluorite

4-D

Octahedral cleavage

Soft, Hardness 4.0

SG 3.0

Colorless, yellow, green, or violet

cubic crystals; transparent

looks like broken colored glass

Galena

3-D, 90°

Cubic

Metallic

Heavy, SG 7.6

Hardness 2.5

Silvery Gray, shiny

Garnet

conchoidal fracture

no cleavage

red to dark brown

vitreous to dull

non-metallic

Very Hard 7.0-7.5

SG 3.5-4.5

Spherical 12,24,36 sided crystals

Gypsum

3-D, 90° and non-90°

no-name or combo

Soft, Hardness 2.0

SG 2.3

White, Transparent to Translucent

Halite

3-D, 90°

cubic cleavage

Salty taste

greasy feel

Soft, Hardness 2.0-2.5

SG 2.0

Colorless, white, transparent

Horneblende

2-D cleavage, non-90°

prismatic non-90°

Hardness 6.0

SG 3.0-3.5

Dark Green to Black

Often shiny

Hematite

fracture

Red color, reddish brown streak (diagnostic)

Hardness varies

earthy to metallic luster

has a red dust

Kaolinite

looks like chalk

No HCL reaction

1-D but too small to see.

earthy luster and odor

Very soft

White or red in color

Becomes plastic or sticky when moistened

Orthoclase

2-D cleavage, 90°(at right angles)

Prismatic 90°

Hardenss 6.0-6.5

SG 2.5

White, Pink, Tan and Dark Colors

No Striations on Cleavage surface

no irridescence

Limonite

fracture

Earthy masses

Yellowish brown to orange streak is diagnositc

Hardness and SG vary

yellowish brown to dark brown

Magnetite

Metallic Luster

Magnetic

Black to Dark Gray

Heavy SG-6

5.2 Hardness

Muscovite

1-D

Pinacoidal Cleavage

thin eleastic sheets

White or silvery in thick masses

Hardness 2.0-3.0

SG 2.8

Olivine

fracture

Olive-Yellowish Green

Commonly granular

Hardness 6.0-6.5

SG 3.5-4.5

Glassy Luster

Transparent to transluscent

Plagioclase

2-D cleavage, 90°

Prismatic 90°

Hardness 6.0-6.5

SG 2.5

White or tan + dark colors

Striations on cleavage surface

occasional bluish irridescence

Pyrite "Fools Gold"

Metallic

fracture

Brass yellow

lacks cleavage

Hardness 6.0-6.5

SG 5

cubic crystals

granular aggregates are common

Quartz

conchoidal fracture; vitreous

Hardness 7.0 (will scratch glass)

SG 2.65

Transparent or Translucent

Hexagonal crystals capped with pyramids

no cleavage

Serpentine

1-D, Pinacoidal

shades of green (rarely yellowish or black)

waxy or fibrous luster (two forms)

Hardness 3.0-5.0

SG 2.5

Sphalerite

6-D cleavage, dodecahedral

Metallic Luster

Yellowish brown; resinous to submetallic luster

Hardness 3.5-4.0

SG 4.0

Yellowish streak