Physical property of minerals Flashcards
Effect produced by combination of wavelength of light incident on the surface of the mineral reaching the observer’s eyes
Color
A play of color or colored reflections exhibited especially by labradorite and cause by internal structures that selectively reflect only certain colors.
Labradorescence (schiller effect)
Optical phenomenon that defines the gem known as moonstone. It is a soft glow of light that floats under the surface of a polished gemstone or under the smooth surface of a gem material.
Adularescence
observed in some semi-translucent to transparent feldspar minerals and is caused by light entering the material and reflecting from molecular interferences within the stone.
Adularescence
Unique optical property on a certain minerals where they change color upon exposure to sunlight and ultraviolet light.
Photochromism/ Tenebrescence
Best example for Tenebrescence
Hackmanite
Transition elements
Chromophores
These are the Transition elements
V, Cr, Mn, Fe, Co, Ni. Cu
exhibits internally various prismatic colors when the mineral is turned.
Play of colors
Appearance of different colors when a crystal is viewed in transmitted light in different directions.
Pleochroism
Two direction has distinct colors
Dichroism
Pearly reflection from the interior of a mineral
Opalescence
Shows a series of colors due to light undergoing reflective interference with itself either on the surface or the interior.
Iridescence
Band of light moves from side to side as in a cat’s eye
Chatoyancy
Six pointed star, formed by a beam of light at right angles at each set of inclusions.
Asterism
Mineral emits visible light when exposed to UV light
Fluorescence
Some fluorescent minerals will continue to glow after the UV light has turned off
Phosphorescence
Some minerals when heated below red hear will emit visible light
Thermoluminescence
When rub it struck with a hammer, minerals will emit visible light.
Triboluminescence
Color of the powdered form of a mineral
Streak
A marked tendency to break or split easily in certain well-defined directions yielding more or less smooth surfaces which are parallel to the crystal surfaces or possible crystal system
Cleavage
3 cleavages, 6 faces at right angles
Cubic
4 cleavages, 8 faces
Octahedral
Example for cubic cleavage
Halite
Example for octahedral cleavage
Fluorite
6 cleavages 12 faces
Dodecahedral
Example of dodecahedral cleavage
Sphalerite
3 cleavages, 6 6 faces not at right angle
Rhombohedral
Example for rhombohedral cleavage
Calcite and dolomite
2 cleavages, 4 faces of many possible angles
Prismatic
2 angle type in prismatic cleavage
90/90 & 60/120
Example (s) for prismatic cleavage
Amphibole, pyroxene, feldspar
1 cleavage, 2 faces
Basal
Example of basal cleavage
Biotite, Muscovite, chlorite
A plane of structural weakness in a mineral
Parting
How is parting different from cleavage?
- It cannot be found in every specimen.
- Not absolutely repeatable/reproducible.
- Caused by pressure
The appearance of the surface of a mineral when it does not break along cleavage planes.
Fracture
Type of fracture where the surface is not interrupted by many noticable protuberances but with few small scales
Scaly fracture
Type of fracture where the surface has no protuberances or very few indeterminate and mostly flat ones.
Even fracture
Type of fracture where the surface consists of flat rounded protuberances accompanied by circular grooves as in clam shells
Conchoidal fracture
Type of fracture where the surface is entirely interrupted by angular large and small protuberances
Uneven fracture
Type of fracture where if certain large parts resembling fibers can be distinguished on the surface as in wood
Fibrous fracture
Type of fracture where the surface is jagged and with sharp edges
Hackly
Type of fracture where the surface is made up of parts resembling planes with length and breadth nearly equal
Foliated fracture
Resistance that the surface of a mineral offers from scratching
Hardness
A number express the ratio between the weight of the mineral and the weight of an equal volume of water at 4 degrees Celsius.
Specific Gravity
Formula for specific Gravity
Density = mass/volume
How measure specific Gravity in the laboratory?
- Jolly or beam balance
- Pycnometer
- Immersing in heavy liquid
Crystallography controlled intergrowths of 2 or more crystals of the same mineral
Twinning
States that: whether there is a center, a plane or an axis of twinning and gives the crystallographic orientation for the twin axis or plane.
Twin law
An imaginary axis about which the crystal s can be rotated to bring into coincidence with other
Twin Axis
A point about which the crystal may be inverted to bring into coincidence with the other
Twin center
A mirror plane reflecting the image of one crystal across it.
Twin plane
A surface or plane on which the two individuals are united
Composition surface
Fizzling sound heard, combined with bubbling seen where a carbonated mineral reacts with an acid
Effervescence
Can be flattened
Malleability
Can be changed in shape by pressure; capable of being drawn into the form of a wire
Ductility
Can be cut by a knife
Sectility
Separates into fragments
Brittleness
Capable of being bent or pulled out of shape
Elasticity
Bends easily and stays bent after the pressure is removed
Flexibility
Property of a mineral to be attracted to a hand magnet
Magnetism
Strongly attracted
Ferromagnetic
Slightly attracted
Paramagnetic
Not attracted
Diamagnetic
Mineral that lack the presence of a transition metal or other magnetic ions
Diamagnetic
Magnetic ions in a mineral have a completely random orientation
Paramagnetic
Magnetic ions in a mineral have a completely random orientation
Paramagnetic
Natural tendency for pairs of magnetic ions to align in opposite direction so that there is spin paring between adjacent magnetic ions
Antiferromagnetism
There is an excess of magnetic ions aligned in one particular direction
Ferromagnetism
A property of a mineral when pressure is exerted along an axis of quartz, a positive electrical charge is set up at one end of the axis and a negative charge at the other end
Piezoelectricity
Induced by heating crystals lacking a symmetric center
Pyroelectricity
7 type of taste (minerals)
- Saline (salt)
- Alkaline (soda)
- Bitter (Epsom salt)
- Sour (acids)
- Astringent (iron vitriol)
- Sweet astringent (alum)
- Cooling (salt Peter)
Example of order (mineral)
- Fetid odor / rotten egg
- Argillaceous odor
- Bituminous odor
- Garlic odor (e.g Arsenopyrite)