- Home
- Rocks
- Type fossils
- Fossil Specimens
- Minerals
- Glossary
- Stratigraphic Chart
- Michel-Levy Chart
- Classification of igneous rocks
- University of Cambridge
- Department of Earth Sciences
- ESC Library
- Moodle
- Sedgwick Museum
- DoITPoMS
- Mindat.org
- Microfossils
- Bryozoans
- Webmineral
- Tree of Life
- CrystalMaker
- Virtual Microscope
Browse Items (264 total)
Sort by:
Alkali feldspar
Formula
(K,Na)[AlSi3O8]
Structure
Framework silicate
Crystal System
Crystal system: monoclinic (-) or triclinic (+) (-)
Physical Properties
Colour in hand specimen: white or pink Cleavage: two at 90° Hardness: 6-6.5
Optical…
Plagioclase feldspar
Formula
Na[AlSi3O8] – Ca[Al2Si2O8]
Structure
Framework silicate
Crystal System
Crystal system: triclinic (+) (-)
Physical Properties
Colour in hand specimen: white Cleavage: two at 90° Hardness: 6-6.5
Optical Properties
Colour in…
Quartz
Formula
SiO2
Structure
Framework silicate
Crystal System
Crystal system: trigonal (+)
Physical Properties
Colour in hand specimen: colourless Lustre: vitreous Pleochroism: none Cleavage: none Hardness: 7
Optical Properties
Colour in…
Hematite
Formula
Fe2O3
Structure
Non-silicate
Crystal System
Crystal system: trigonal (-)
Physical Properties
Colour in hand specimen: black, steel-grey and bright to dull red Streak: cherry-red Cleavage: none Hardness: 5-6
Optical…
Magnetite
Formula
Fe3O4
Structure
Non-silicate
Crystal System
Crystal system: cubic
Physical Properties
Colour in hand specimen: blackStreak: blackCleavage: noneHardness: 7.5-8
Optical Properties
Colour in plane polarised light: almost…
Pyrite
Formula
FeS2
Structure
Non-silicate
Crystal System
Crystal system: cubic
Physical Properties
Colour in hand specimen: pale brassy yellow; black when fine-grainedStreak: greenish or brownishLustre: metallicCleavage: not…
Galena
Formula
PbS
Structure
Non-silicate
Crystal System
Crystal system: cubic
Physical Properties
Colour in hand specimen: lead greyStreak: lead greyLustre: metallicCleavage: one, perfectHardness: 2.5
Optical Properties
Colour in plane…
Gypsum
Formula
CaSO4∙2H20
Structure
Non-silicate
Crystal System
Crystal system: monoclinic (+)
Physical Properties
Colour in hand specimen: usually white or colourlessCleavage: rhombohedral, one perfect, two distinctHardness: 2
Mineral…
Anhydrite
Formula
CaSO4
Structure
Non-silicate
Crystal System
Crystal system: orthorhombic (+)
Physical Properties
Colour in hand specimen: white or colourless when pure Cleavage: two at 90° Hardness: 3-3.5
Optical Properties
Colour in plane…
Calcite
Formula
CaCO3
Structure
Non-silicate
Crystal System
Crystal system: trigonal (-)
Physical Properties
Colour in hand specimen: whiteCleavage: rhombohedralHardness: 3
Optical Properties
Colour in plane polarised…