[MetE 16] Physical Properties of Minerals: Cleavage and the rest

Octahedral Symmetry

Dodecahedral symmetry

Parting

resembles cleavage but only shown in twinned or pressured

Octahedral parting

Basal parting

Rhombohedral Parting

Fracture

breaking of crystal where strength of the bonds is identical in all directions

Conchoidal

shell-like

Fribrous and Splintery

Hackly

Broken metal piece

Irregular

Tenacity

resistance of mineral to crushing, bending or tearing

Brittle

breaks and powdrs easily

Malleable

can be hammered into thin sheets

Sectile

can be cut into shavings with a knife

Ductile

can be stretched into wires

Flexible

bends but does not snap back

Elastic

bends and snaps back

Specific gravity

• relative density

• ratio between weight of substance andt he weight of equal volume of water

Jolly Balance

Torsion Balance

Pycnometer

Vitreous

Resinous

Pearly

Greasy

Silky

Adamantine

Play of colors

interference of light

Chatoyancy

shows band of light at right angles to the length of the finbers or direction of the inclusion

Asterism

6 pointed satr when light hits right angles

Luminescence

emission of light by a mineral

Fluorescence

glowng yes

Thermolumnescence

Emitting visible light when a substance is heated below red heat

Tribolluminescence

Luminous by crushing, scratching or rubbing

Piezoelectricity

electricity from pressure

Pyroelectricity

temp may cause electricity

Ferromagnetism

magnetism observed in metallic ions

Paramagnetism

temporary magnetism

Diamagnetism

repelled by magnetic field