I was wondering if anybody knows the difference between chalecdony, onyx, and agate. I know that they're all a type of quartz, but could not find any real differences between the three minerals. I have to classify these minerals for Science Olympiad, and their guidelines list them as two distinct minerals(quartz: Agate/onyx and quartz: chalcedony).I did some research, but it all seems to contradict with each other. If anybody could please clarify, that would be great!
119959
chalcedony is the family name of a group of microcrystalline quartzes, confusingly chalcedony is also the name of one of the family members. The only real difference is the colour, and the banding patterns. the names are traditional rather than geological, the rocks having been used for jewellry and ornamentation long before geology was thought of.\nAgate is asymetrically banded with a wide range of colours\nOnyx has parallel bands and is predominantly black/white\nChalcedony has a bluish colour.
216538
A student from New Delhi showed me some Kashmirs he had purchased last year.  They were indeed Kashmirs (we checked the inclusions) but they were one of the worse cut stones I'd ever seen.  Plus they were badly zoned with (at best) a fair color grade.  \n\nMy point is, the finest Kashmirs (and I've seen some at the Christies auctions) are the most beautiful, vivid yet velvety blue sapphires on the face of this earth.  But your average Kashmir could be as average as a sapphire from any other locality.  \n\nI understand the buzz about origin (Golconda Diamonds/Kashmir Sapphires/Mogok Rubies etc), but we shouldn't judge gemstones by their "genetics".  I've seen fine Burmese sapphires that would have knocked the socks of Kashmir enthusiasts.  \n\nPrices for fine Kashmirs? It's a seller's market! That's the best (and worse) thing about fine quality colored gemstones.  They are so genuinely rare (as opposed to diamonds) they are worth whatever someone will pay for them!
59418
Here's the pages with the info. You'll have to read fast. Don't wait so long next time. Good Luck!!\n\nhttp://mineral.galleries.com/minerals/gemstone/aquamari/aquamari.htm\n\nhttp://mineral.galleries.com/minerals/silicate/garnets.htm\n\nhttp://mineral.galleries.com/minerals/gemstone/class.htm
21863
Mohs' hardness scale is somewhat arbitrary.  Moh tried to find commonly available minerals that were about equally spaced in hardness.  Talc was arbitrarily assigned "1."\n\nAs one example of the inconsistency, diamond (Moh's 10) is about 10 times harder than corundum (Moh's 9).\n\nThere should be some minerals sites out there that allow you to list minerals in order of Moh's hardness.  There may also be some with Vicker's hardness for comparison.\n\nThe main advantage of Moh's hardness scale is its practicality for field use.\n\nA lot of the sheet silicates are very soft.  In the soft ones, the only forces holding the sheets together are van der Waal's forces, which are quite weak.\n\nClays are very soft.  The crystals are very small and only van der Waals forces act between them.  (They are also sheet silicates, but the sheets are held tightly together by cations.)
136748
Try Wikipedia:\n\nhttp://en.wikipedia.org/wiki/Minerals
24681
You can make a crystal by combining diff. elements...\n\ne.g:\ncombining carbon, hydrogen and oxygen will result to glucose molecules which will made up to SUGAR CRYSTALS.\n\nI think these are some of the diff. kinds of crystals...\n\nIceland SPar\nAlbite, orthoclase, pyrite, apophylite, anhydrite, quartz...
309180
hard to say. i found lots of things in the desert. my husband is a geologist. if you mail me a picture, i will have him look at it.\nthere is lot of crystal stuff in egyptian deserts, most are worthless unless you enjoy it as decoration in your house. does it has a greenish tone in the bottom of the crystals? i have lots of them. it depends also where you found it. if it was near a roman settlement, it could be ancient glass, but if it scratch glass now, i doubt it. i found lots of this, but not this big of a piece, that would be uncommon. tell me more about it, maybe i can help you.\n\nsend me a picture...susuegypt@hotmail.com
471669
AgNO3 + NaCl => AgCl(white ppt) + NaNO3\nAgNO3 + KI => AgI( yellow ppt) + KNO3\n\nthere is a change of color because AgI is produced
452118
You should recognize that, when they combine with nonmetals, metals tend to LOSE electrons and form POSITIVE ions. Nonmetals, on the other hand, tend to GAIN electrons and form NEGATIVE ions.\n\nGet an "A".
552464
Aquamarine is a blue beryl. Beryl with other mineral impurities that have turned it green is emerald. Pure beryl does not have a remarkable color, but if the crystal is called beryl, it's usually in the red-orange-yellow range.\n\nBeryl forms from pegmatites, the fluids left over when magma begins to crystallize deep inside the earth. These fluids flow into cracks in the rock and and form huge crystals shaped in sheets. If these fluids are rich in beryllium, they crystalize to become beryl.  So, you will find them in volcanoes, especially when the material on top has eroded away to bring the surface nearer to the ancient magma chamber.\n\nBeryls, emeralds, and aquamarines are notably found in Spain, Russia, Namibia, Madagascar, Pakistan, Colombia, Brazil, North Carolina, and San Diego County, California. Most beryl crystals are small, but some discovered in Colombia may be more than 5 meters in length. One beryl discovered in Madagascar weighed 36,600,000 kilograms!  \n\nAquamarines are actually quite inexpensive. You may be able to buy a loose one carat aquamarine on eBay for less than US$5 (I can't testify to the clarity or quality of such gems.) For a little bit more money you can buy them set in jewelry. I'm very fond of the aquamarine earrings I've been wearing for about three straight days now!
374992
Several.  I have a few pieces of Amber that I love, a few China Red Quartz, and Aventurine are my favorites.  Amber helps me to feel centered and true, Red Quartz is a wonderful stone to use for directing energy and Aventurine is my "lucky" stone--everything seems to go right when it's around.  I don't feel that gems hold special powers but rather they are tools to attune to those powers or direct them.\n\nMy favorite book on the subject is "Love is in the Earth: A Kaleidoscope of Crystals" by Melody
406219
dairydahm is right!  It's conglomerate.  Sedimentary (so you were right, too) rocks can contain pebbles of similar or varying sizes, depending where it formed.  Below are some sites that have pics of conglomerates for you to check--if you don't believe us.  (I'm a geology teacher, by the way.  (-; )
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Crystal structure depends primarily on the size of the ions. The Cs+ ion has one closed electron shell more than the Ag+ ion. Therefore more Cl- ions can be packed around a Cs+ ion than around a Ag+ ion.\nCompare these two structure to see what I mean:\n http://cst-www.nrl.navy.mil/lattice/struk/b1.html          AgCl\n http://cst-www.nrl.navy.mil/lattice/struk/b2.html         CsCl
5266
When people say "glass," they usually mean soda-lime glass.  That is made by mixing fluxes, soda ash (Na20) and lime (Ca0) with quartz and melting the mixture.  Soda and lime reduce the viscosity of the melt.\n\n"Fused quartz" is a glass (i.e. noncrystalline) that is made by melting quartz (or synthetic silicon dioxide) and cooling it too fast for crystals to form.  You can make fused quartz, but it is difficult to handle because it is so viscous.  Unless you need the properties of fused quartz, you would be better off to melt some glass.
59026
A. Pyrite and magnetite are both from the same crystal system. That means they form crystals in a similar shape or pattern. They are both from the isometric system. They will both be blocky crystals but may not be exactly the same. Perfect pyrite crystals are cube shaped or diploidal (see:http://webmineral.com/data/Pyrite.shtml), and magnetite is an octahedron (see: http://webmineral.com/data/Magnetite.shtml).\n\nHardness of magnetite is 5 1/2-6 on Mohs scale and pyrite is 6- 6 1/2.  \n\nBoth have conchoidal fracture. (Quartz has conchoidal fracture in case you need to picture this)\n\nBoth have a similar density. Pyrite has a density of 4.8-5 g/cc and magnetite has a density of 4.95 gm/cc.\n\nBoth have a metallic luster. \n\nB. The best way to distinguish between them is to use a streak test. Magnetite will be grayish-black and pyrite will be greenish-black.\n\nThe other major difference is that magnetite will be naturally magnetic, and pyrite will not be. \n\n\nThe lesson here is to learn think of your different properties as sort of a tool kit. Decide which properties are useful and which ones will not be useful for the particular samples you are testing. Be sure to be familiar with all of the properties you can use. A list would be:\na. cleavage\nb. color (one of the least reliable)\nc. density\nd. luster\ne. fracture\nf. crystal habit (can be confusing because some minerals have several possible)\ng. hardness (know the hardness of common tests like a penny, a knife, a quartz crystal, glass, etc.)\nh. streak\ni. magnetism\nj. taste (best test for Halite or sylvite)\nk. There are lots more that involve using thin sections in a microscope, and X-ray diffractometer, etc.
299995
Here are some questions that will help you:\n\nFirstly, are they natural or synthetic?  \nSome synthetics can look amazingly similar to heat-treated naturals.  \n\nIf they are synthetic, what kind of synthetics are they? Flame-fusion? Flux-grown? Flame-fusion synthetics can be had for a few cents a piece.  Some flux-grown synthetics cost over a $100/ct.\n\nIf they are natural, you'll need to judge their quality:\n\nColor - Is the color saturated? Is the tone balanced? Do they show undesirable brown modifiers? \n\nClarity - Are there inclusions? How distracting are they? Where are they located? Do they improve or adversely effect the aesthetics of the stones?  Do they affect durability? \n \nCut - Are the stones faceted or cabachon-cut? Are they transparent, translucent or opaque?  What shapes are they?\nAre they cut well? ie balanced & symmetrical, good length-width ratio, good polish and finish.  There is a premium for matched pairs and lots.\n\nCarat - 13 rubies totalling 50 carats makes each piece about 3.85cts.  Hmmm...that's considered large for rubies.  \nFine stones above 3 carats are considered rare.  Commercial & utility quality stones can be hundreds of carats in size and still not be very valuable.\n\nOrigin - Where were they mined? There is a premium for Burmese stones, especially from Mogok.\n\n------------------------------------------ \n\nBased on the information you have provided, it is not possible to accurately say what they are worth.  You could have a jeweller look at them, but it's probably better to send them to a professional colored stone appraiser.  \n\nAs a very rough estimate, here are some price ranges for faceted rubies in the 3ct range (in Bangkok): [Commercial/Good/Fine]\nRuby [25-300/300-1000/1000-6000]\nPink Sapphire (low saturation rubies) [50+/100-250/250-1500]\n\nBTW, 99% of all rubies available in the market are heat-treated.  A premium is put on stones that are not heated but only if they are of fine quality material.  All other things equal, washed out stones that have not been heat treated are never worth more than heated material with good color.
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Do the diamonds and gemstones bring the opportunity? Or does the brand "Chatham Created Diamonds and Gemstones" bring the opportunity?\n\nIf it's the former, #1 is correct. If it's the latter, #2 is correct. \n\nEither way, "Chatham Created Diamonds and Gemstones" is the subject, and "opportunity" is the object, so it doesn't matter that "opportunity" is singular.