What are the physical properties that geologist use to identify mineral and a small summary of each?

Question

like what each property means like clarity u can see thorugh it ect.

Answer 1

Colour- the colour of the mineral; not very reliable except in a few cases

Luster - the metallic or nonmetallic look of the mineral. Non metallic has several sub groupings (vitreous, waxy, greasy, etc.)

Streak - the colour of the mineral when powdered

Habit - the symmetrical patterns the crystal structure makes

Cleavage - the tendency for a mineral to break along parallel planes of weakness

Hardness - Placement on the Mohs scale of hardness

Reaction to acid - pertains to carbonate bearing minerals in HCl

Magnetism - some mineral will attract a magnet

Striations - some minerals (like plagioclase) display striations.

Answer 2

Hardness - determined by scratching the mineral with different materials to obtain an approximate hardness on a scale from 1-10.

Color - not always the best one as some minerals can be many different colors, many minerals have the same color, but diagnostic for some minerals

Transparency - how clear the mineral is. Ranges from transparent (can see clearly through) to translucent (see light through) all the way to opaque (cannot see through at all, not even light)
Lustre - whether the mineral has a glassy shine (vitreous), or a metallic look, sub-metallic look, earthy (dull), greasy, waxy, adamantine (like a diamond), pearly

Specific Gravity - a relative measure of how heavy a mineral is compared to the same volume of water.

Streak - generally used for sub-metallic and metallic minerals, can be quite diagnostic of the mineral. For instance, hematite has a red streak

Magnetism - is the mineral magnetic? Ex: magnetite

HCl test- for carbonates, pour on the mineral. If it fizzes and creates bubbles then its a carbonate. Some carbonates don't fizz unless you scratch them first or heat the HCl

Cleavage - can be quite diagnostic. A mineral with this property will tend to break along planes of weakness which are the cleavage planes. Often the cleavage will be given in Miller Indices

Fracture - in minerals lacking cleavage (ex: quartz, which has a concoidal fracture - think the circular fractures in glass). Basically a generalized way the rock breaks in the absence of cleavage

Form/Habit - the actual shape of the crystal - prismatic, dodecahedrons, octahedrons, plates, etc. Related to the arrangement of ions in the mineral, giving rise to symmetry elements including rotation and rotoinversion axes, mirror planes, and centers of inversion. These symmetry elements can be found in mineral specimens and used to determine the crystal class when used in conjuction with Miller Indices.

Twinning - Some minerals have characteristic twinning, which is basically two crystals intergown that share a common twinning surface/composition plane. Twinning can give rise to things such as striations in feldspars (due to polysynthetic twinning) Polysynthetic twinning is when there are several twins with the same alignment (especially common in feldspar). There are several different types of twinning including interpenetration twins (staurolite), simple/contact twins (quartz), etc.

See wikipedia or any mineralogy textbook(not a mineral field guide) for more detailed information. There are more properties under the petrographic microscope.



Taste/smell - some minerals taste salty, some smell like sulphur or other things, related to chemistry

Answer 3

You can also add to the list:

Specific gravity - a measure of how dense the mineral is.

Transparency - Whether the mineral is transparent, transleucent or opaque.

Taste - some minerals have a distincive tase. HOWEVER, YOU SHOULD NEVER TASE A MINERAL UNLESS YOU KNOW WHAT IT IS, ELSE YOU RISK POISONING YOURSELF!!!

There are also more complex optical properties that can be examined under polarised light.

Answer 4

You know how they say something like "We fell into each other's arms?" That almost literally happened with my parents. My aunt was moving out of my grandparents' house, and her friend helped her move, and he knew my father, and so my father went along for the ride when my aunt's friend helped her move, and my mother was tagging along for the ride, as well, and when my mother got in the back seat of the car, my father was already sitting there with his arm out and resting on the back of the seat, as if it was an arm rest, and my mother ended up sitting where my father's arm was extended out. So, my parents met in the back seat of a car, with my father's arm around where my mother sat down.