Is any mineral softer than talc?
816570
Yes talc is a mineral. Talc is the softest mineral on Moh's hardness scale.\n\n10 Diamond  HARDEST\n9 Corundum  \n8 Topaz  \n7 Quartz  \n6 Feldspar \n5 Apatite\n4 Fluorspar\n3 Calcite\n2 Gypsum \n1 Talc  SOFTEST
652471
don't use too much talc powder, it isn't good for you.
736173
Diamonds are the hardest natural material; but there are harder man-made materials. \n\nAggregated Diamond Nanorods (ADNR) were developed last year. ADNR can scratch natural diamonds, thus ADNR is harder than natural diamond and consequently more resistant against abrasion. \n\npolyyne, a superhard molecular rod comprised of acetylene units - that resists 40 times more longitudinal compression than a diamond. Ironically, these glittery gems are comprised from the element carbon and have the weakest type of chemical bonds, while polyyne has the strongest bonds in carbon chemistry. \n\nI wasn't able to find a comparison of polyyne and ADNR, but I believe ADNR was developed first and held the title until polyyne was developed a short time later. I'm not positive about the order though. Either one is harder than my head which is saying something.
621837
neither granite nor obisdian are minerals they are two different types of igneous rocks. basically molten granite cools slow generating large crystals, obsidian cools very fast giving it a glassy look and making it nearly impossible to pick out individual crystals
961539
My brain? just kidding,\nphenakite?\ncalcite?\nquartz?\nnumber one choice= aragonite!\ndolomite\ngypsum\nor maybe a combination of calcite and dolomite\n\nWhy the curiosity? Precious gem!\n(congrats on the 2000 points)
853580
It's softer - hence less friction hence no spark
198982
hardness, luster, clevage, composition, crystal structure\n\niron is useful also in the mineral gypsum they use it to make drywall\n\nmost gems are valueable because they form extremely slow making them rare, they are also the very hardest type of mineral
367986
The two hardnesses you are looking for must be scratch and indentation hardness.\n\nScratch hardness is caracterized by the Mohs scale (as commented before).\n\nIndentation hardness is caracterized by serveral scales, the most popular (here, in colombia) are the Rockwell hardness test and the Shore durometer.\n\nThe wikipedia link has in itself references to detailded information about many hardness scales that you may find useful
400219
Well, it won't be easy.  The two differ only in one way: Spessatite has Mn, while Hessonite (which is a subtype of grossular) has Ca.  The colours are also similar: Spessatite is ususally deep red but may also be black to orange, dark pink, or brown.  Grossular/Hessonite is more likely to be nearly colourless to green, yellow, pink, or brown.\n\nThe best way to tell them apart may be by the assemblage in which they occur.  Hessonite tends to be more commonly associated with skarns and other metamorphosed carbonate-bearing rocks, and is usually associated with calcite, dolomite, wollastonite, tremolite, and epidote.  Spessatite on the other hand tends to more commonly occur in granites, pegmatites, and other felsic igneous rocks, and in Mn-rich metamorphic rocks.\n\nThe only sure way to tell though would be to put them on a microprobe to find out.\n\nGood luck!
96253
Calcite...my favorite mineral!!! (Calcium carbonate, get it?)\n\nHardness is the most obvious. Calcite is 3 on Moh's scale. Quite soft! and quartz is 7.\n\nA penny, a nail or knife, a glass plate, all will help you separate these two. The quartz will scratch everything there. \n\nOne more test, that I didn't put on your other list that is the best test here, the acid test. A dilute acid will fizz when applied to the calcite, while the quartz will not react at all. This is why all good geologists carry around a bottle of acid in the field. Quartz (sandstone) and calcite (limestone) can be deceptively similar in appearance. \n\nThese two are good examples of why you cannot rely on just color or shape. Both quartz and calcite come in a variety of colors, depending on the impurity, and both can be completely opaque.(Think of rose quartz, milky quartz, amethyst, etc, and realize that calcite has as much variety) Both can be very similar crystal shapes since they are both in the trigonal system. Both have a white streak. Both have a glassy (vitreous) luster. \nCalcite:\nhttp://webmineral.com/data/Calcite.shtml\nQuartz:\nhttp://webmineral.com/data/Quartz.shtml\n\nThere is one more online resource I think you should look at:http://www.mindat.org/\nWebmineral.com is better for the questions you have asked, but mindat.org is very comprehensive and will have photos of more variations of the minerals that might help you understand the challenge of picking which properties are best for which minerals. On a lab test, you may be given samples to test that you have never seen, and they may be minerals you have seen before but in a different form (yes- its a trick), so knowing your tests can save you.\n\nBy the way, I just noticed your question about why color should be used with caution for identifying minerals. I think this answer is a good example of that. Many minerals come in many different colors due to some small impurity in the mineral. Both quartz and calcite come in almost every color of the rainbow. Fluorite is another good example of a mineral that can come in many different colors. Other examples are the many copper compounds which come in various shades of blues and greens. Because there are so many different copper minerals with the same color you can't use the color as a diagnostic for any one of them.
807640
Baby powder or talc, or if you really mean it anti-perspirant on the hands.
835925
Generally sandstones and quartzites are more weathering resistant. They tend to form mountains and ridges. Limestones and shales tend to weather more and form valleys. They can't hold a mountain up. \n\nDifferential weathering is where different formations or even bedding within the same formation, weather at different rates. Softer, less competent rocks weather faster than harder, more substantial rocks. Look at a road cut, some rocks stick out like massive sandstones, and underlying shales have weathered back into the hillside. The rocks have experienced the same weathering forces, but the shales have weathered faster. Look at a cross-bedded sandstone. Some bedding is prominent and sticks out, some has eroded back in the formation. Both are differential weathering.\n\nIn the big picture, the rocks on a mountain have resisted weathering, where the rocks in the valley floor have succumbed, Differential weathering.\n\nThe last part of your question; think of a cemetery. Which gravestones last the longest? Lots of pink granite ones, huh? Granite is a very hard metamorphic rock. It is the most resistant to weathering. Marble is metamorphosed limestone. Much harder than limestone, but still CaCO3 (Calcium Carbonate). Rain is slightly acidic, so marble will weather out, but very slowly. Sandstone is a sedimentary rock, softer than granite or marble. So there is your answer.\n\nI hope this helps.
661108
Try using a talc powder, like Shower to Shower
35605
it doesnt really matter. but when your on a soft surface its better for your back. when your on a hard surface it can be bad for you back. so i think soft is better.
362435
Montmorillonite's water content is variable and it increases greatly in volume when it absorbs water. Chemically it is hydrated sodium calcium aluminium magnesium silicate hydroxide (Na,Ca)x(Al,Mg)2(Si4O10)(OH)2·nH2O. Potassium, iron, and other cations are common substitutes, the exact ratio of cations varies with source.\n\nI would assume it could be magnetic, but not always. As for the affect/reaction I didnt find any information either way.
105777
I'm going to turn to Wikipedia's definition of a mineral first because I like it (I quote)\n\n"To be classified as a "true" mineral, a substance must be a solid and have a crystal structure. It must also be an inorganic, naturally-occurring, homogenous substance with a defined chemical composition.”\n\nWhat does this mean in terms of your question? There are countless different physical properties of minerals, but you must understand that a couple of key things make a mineral fit the definition. It must be inorganic (Encarta is just wrong here- petroleum and coal are not minerals in any sense and are organic compounds that came from living organisms) . It must have a consistent and homogenous chemical structure (another reason coal and oil don't qualify). It must be naturally occurring. Chemists can make lots of compounds in the laboratory that don't occur naturally. So the most important properties are the chemical composition which must not be a mixture (like a rock has). Obsidian has a consistent chemical structure but because it has no crystal structure it is considered a mineraloid, not a mineral. Cristobalite crystals may occur within obsidian, and cristobalite is thus considered a mineral. Another example of how crystal structure determines a mineral is to compare calcite and aragonite. Both have the exact same chemical formula, calcium carbonate. Because they have different crystal structures they are different minerals. \n\nSo the short answer:\n1. inorganic\n2. crystal structure \n3. chemical homogeneity\n4. naturally occurring\n5. solid
687420
Talc\nGypsum\nCalcite\nFluorite\nApatite\nFeldspar\nQuartz\nTopaz\nCorundum\nDiamond