Does anyone know how to tell the difference between onyx, alabaster, & marble?
357935
onyx is a type of quartz ( main constituent silicon)\nalabaster is a form of gypsum (main constituent sulphate)\nmarble is a  form of chalk or limestone ( main constituent  calcium carbonate)\n\nto determine which is which if you have 3 samples, identify alabaster first, alabaster is the softest, either of the others will scratch it.  Between marble and onyx, marble can be identified by dropping a few drops of weak hydrochloric acid on to it, the acid will 'fizz' on the marble as the calcium carbonate reacts with the acid to produce hydrogen gas ( if you dont happen to have any weak hydrochloric acid lying about, use a drop or 2 of kitchen descaler, it is weak hydrochloric acid, and works on exactly the same principle)
787407
Yep, definitely cleavage (lol and you can describe how many directions the cleavage is in and whether it's 'perfect cleavage'... a great opportunity for geokes..)\n\nHardness is the resistance of the surface of the mineral to scratching, it's dependent on the crystal structure of the mineral, and usually expressed on 'Moh's Hardness Scale' - as a number from one to ten, one being lowest (talc, where talcum powder comes from, has a hardness of 1; diamond has a hardness of 10)\n\nThe streak is the colour of the mineral when powdered (it is useful in identifying minerals as it is a more constant property than colour - the slightest difference in trace element chemistry might have a huge effect on colour, hence all the diff varieties of quartz...). Streak is usually found by scratching the mineral along an unglazed piece of porcelain.\n\nFracture is the way a mineral breaks when it doesn't break along a plane (flat surface).
1001175
How to answer this?  I actually have several books entirely on how gems are faked or modified and the con census is that it can be difficult at best.  To find out what sort of stones you are likely to find in any given area do a general search on the geology of it and the surrounding countries.  If you are lucky he might find some Persian Spider Web Turquoise from Iran (though the mines are supposed to be played out now) as you should figure in the trade routes between the other countries as well.  I know the area is copper rich so turquoise and malachite almost certainly.  Try doing a search on "GEMS OF AFGHANISTAN".  From there you can refine your search parameters and add in secondary searches of fake and altered stone.  By the way, fake and altered are not the same as many gems can be treated by heat, radiation and other methods to improve the quality.  They are still the same type of gem just a better grade than they started out as.
381199
that'll be chalcedony. it differs from quatrz in it's shape, as it usually occurs in botryoidal masses, whereas quartz occurs more in hexagonal prisms. chalcedony is similar to opal, but can be distinguished by its higher specific gravity. it can be formed as a dehydration product of opal, hence the connection. the colour is highly variable, as it can be white, blue, red, green, brown or black, and varieties of chalcedony include jasper, agate, chrysoprase, onyx and carnelian. it's formed in rock cavities, especially lavas, and it develops at relatively low temperatures, whereas quartz occurs in any rock type, and usually formed at higher temperatures
87607
Most multi-colored raw onyx is found in Brazil, but it can be found worldwide in places such as Italy, US, and Mexico (although Mexican Onyx isn't an Onyx, but usually either a Calcite or an Agate). Onyx may be brown, white, grey, or black, although the color most commonly associated with onyx is black. The name onyx comes from the Greek word for fingernail. Mythology states that Cupid cut the fingernails from Venus with an arrowhead while she was sleeping. The fates then turned the scattered clippings on the ground into stone so that no part of the goddess would ever perish. The reddish brown and white version of onyx known as sard onyx was highly valued in Rome, in particular for seals because it was said onyx would not stick to the wax. Sard onyx was also used as protection against incantations and sorcery. Mexican Onyx (white and brown) is believed to aid in sleeping. Some spiritualists believe that black onyx can help to change habits. It can help with objective thinking, spiritual inspiration, and the control of emotions and passions, which helps the wearer move beyond bad relationships and old hurts. Some claim onyx can help physical ailments such as hearing problems, heart trouble, and ulcers. Onyx is also believed to improve concentration and devotion. It may be for this reason that it is often used in rosaries.
820767
There is no real way of telling them apart, they are what you call sexually monomorphic and monochromatic, meaning they have no physical difference or difference in color. The females are slightly larger than the males, but you would only really be able to tell them apart if you had both in your hands. Under a microscope with some entomological knowlegde, you would be able to see the genetalia, but with the naked eye, it is quite difficult.\nThe best way to tell would be to find a pair in copulation, the one on the bottom is the female and the one on the top is the male. Seeing this will also give you an idea of the size of a female compared to the male....but thats about all....\n\nHope this helps!
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glistening enchanting magickal scary dark gloomy vivid(ly) ablazed spectacular amazing crystalline mesmorizing glowing sparkling.That's all I got for now!Good luck!
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On one axis type, the other size.\nOn one axis color, the other size.\nOn one axis toxicity, on the other, size.\n\nAny of those are interchangable.
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Just guess what the colors would be for different compounds before you actually do the flame test for the hypothesis.  \nOr you could guess whether it is the cation (the positively charged metal ion) or the nonmetal anion that is responsible for the different colors.
146546
Check ebay, just be careful. I got a chipped Tanzanite once. On the other hand, I have bought some really nice stones there, too.
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K2S\n\nPotassium is K.  Sufide is S2-, so you need 2 K's.
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Classics IV\n\nhttp://en.wikipedia.org/wiki/Classics_IV
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Here:\n\nhttp://gempond.com/odc/
58366
You can read about both of them on Encarta. Don't just take my word, they are different, learn why they are different there.
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http://www.explorationdesign2.com/generic33.html\nhttp://www.leisurepro.com/Cat/Assorted_Accessories/974.html
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see link below.. if the name isnt there.. im not sure what to tell.
239205
GO TO AN APPRASER AND THEY CAN TELL YOU IF IT IS OR NOT