what are some differences between a rock and mineral?
552288
rocks are made up of minerals
828414
We are dealing with an illusion caused by grain size and moisture content here.  In fact sand is quite hard because it is made up of individual rock and mineral grains.  Limestone and quartz are pretty hard materials.  If a sand is damp, or has very small rounded grains, it can feel soft to the hand however.\n\nClays on the other hand are soft because they are created by the chemical weathering of other minerals (such as pyroxene or feldspar) and the individual clay units are microscopic in size.  Clays usually contain a high proportion of water in their structure as well (it can be as high as 70%).\n\nWhen a geologist in the field can't make out the whether a rock is a siltstone (clastic) or clay (chemical) because the grain sizes are too small to see, a simple test is to break off a small fragment put it between ones teeth.  If its chewy and soft, its a clay.  If its hard and gritty, its a silt. \n(Warning - experts only folks.  Some rocks contain poisonous minerals so don't go around randomly tasting rocks.)
937460
There is a whole battery of scientific tests used in mineral identification today however there are a number of tests that have been in use for a very long time which still work well.\n1) Observation - what does it look like, colour, the streak it leaves on an unglazed tile. the weight in your hand etc.\n2) Hardness. Its resistance to being scratched by a range of other minerals (Moe's scale)\n3) Density - how much it weighs compared to the same volume of water.\n4) The shape and form of its crystals.\n5) Chemical analysis.\nIf you put these together with a lot of experience there are not many minerals you cannot identify.
322954
Try Wikipedia:\n\nhttp://en.wikipedia.org/wiki/Minerals
554793
Cleavage\nUsually occur in smaller scale,\nReflect internal structure of rocks and crystals\nUsually more regular nature in shape and spacing\nRelatively flat and smooth discontinuity surface\n\nFracture\nUsually occur in larger scale\nReflect external stress field of rocks more\nUsually more irregular nature\nRough and jagged discontinuity surface, sometimes accompany tiny pieces of the brocken material.
822515
A mineral can be defined as:\nsomething that is naturally occuring\nsolid\nhas an exact chemical composition\norderly arrangement of internal atoms \n\nwhen different minerals are combined that is what makes a rock. for example granite. Is made of the minerals quartz, pottassium feldspar, muscovite, plagioclase feldspar, and amphibole.
849041
A rock is a naturally occurring aggregate of minerals and/or mineraloids. Rocks are classified by mineral and chemical composition, by the texture of the constituent particles and by the processes that formed them. These indicators separate rocks into igneous, sedimentary and metamorphic. They may also be classified according to grain size, in the case of conglomerates and breccias or in the case of individual stones.\n\nMinerals are natural compounds formed through geological processes. The term "mineral" encompasses not only the material's chemical composition, but also the mineral's structure. Minerals range in composition from pure elements and simple salts to very complex silicates with thousands of known forms (organic compounds are excluded). The study of minerals is called mineralogy.
244328
no a diamond is a type of rock.\n\na crystal is a type of glass.\n\nsimilar, but not quite the same.
719643
This depends on the mineral being formed. For instance, silicate based minerals (from igneous rocks) are fromed by the cooling effect of molten lava. The size of the mineral formed is dependant on the length of time the 'lava' has to cool. This process is called crystalisation. \nIn sedimentary rocks, minerals are formed by erosion, chemical changes, de-salination (extraction of water, although the mineral was present in the water to start with i.e halite), pressure and temperature.
900927
Well, in things like pegmitites, late stage crystalized rocks, you can have very high amounts of incompatable elements, like Li, Au, Ag, B, Zr, and many more.  That's why you get minerals like beryl, lepidolite, tourmaline, etc.
551728
If you are asking how rocks are formed, there are three main processes: 1) Igneous rocks are formed by the solidification molten magma from deep in the earth; 2) Sedimentary rocks are formed by pressure acting on sand or other small fragments under a body of water or under other rock layers; 3) Metamorphic rocks start as another type, but are changed into a different, often more complex structure or crystalline matrix by the action of pressure, heat, friction, and/or water.
974922
rocks : see http://en.wikipedia.org/wiki/Rocks\nlakes : see http://en.wikipedia.org/wiki/Lakes
213385
there are a few diff. types of crystals....there's hard rock candy crystals, crystal ball, crystal chandelier...crystal meth...they pretty much speak for themselves.
654586
Igneous rocks-- formed from magma, extrusive or intrusive.  extrusive have small crystal forms ex. basalt, scoria, pumice.  Intrusive large crystals forms ex. granite, gabbro\n\nSedimentary rocks -- the only rocks that contain fossils, formed at the surface, formed from fragments of other things ie. rocks, fossils, woody plants (coal), or minerals crystallizing out of water (limestone) -- Are porous found in aquifers, oil fields.\n\nMetamorphic rocks -- forms from alteration of other rock with increased pressure and/or temperature.  Always in a solid state (they don't melt)called recrystallization, form new minerals that are stable at increased temperature and/or pressure, happens below the earth's surface (at depth).
29998
The differences are that chemical change is when it chemically changes the elements, such as H2O. Physical change is a change where you can physically change substances, such as when you mix salt with water with a spoon. The similarities are that they both combine 2 substances together to create a new compound, I think.       *No guarentee this is correct*
78252
If I remember correctly from my science classes, a mineral is essentially a solid substance that has a crystal structure.  (That's two right there - It's solid, and has to be crystal in structure.)  It also has to be inorganic and occurs naturally, and also homogenous.  Not to mention the fact that it's supposed to have a defined chemical composition.  That's more than four characteristics, but I believe them to be all true of minerals....
682891
Some minerals may also be fluorescent under ultraviolet light, that is they absorb UV light and emit in the visible. Other optical properties such as index of refraction and pleochroism (differential light absorption) require an optical microscope to measure.  Certain minerals that display fluorescent properties also display a multicolored effect when having ample illumination with ultraviolet light.