Classifications of crystals?
402991
if you are talking about lattice structures then all the basic ones can be found on this website:\nhttp://members.iworld.net/joo/physics/curri-sub/crystal/lattice.html
462771
They're polyhedrons.  The 5 types are:  Tetrahedron (a 3-d figure with 4 equilateral triangle faces, 4 vertices, & 6 edges); Cube (a 3-d figure with 6 square faces, 4 vertices, & 12 edges); Octahedron (a 3-d figure with 8 equilateral triangle faces, 6 vertices, & 12 edges)); Dodecahedron (a 3-d figure with 12 regular pentagonal faces, 20 vertices, & 30 edges); and Icosahedron (a 3-d figure with 20 equilateral triangle faces, 12 vertices, & 30 edges).
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.
1152488
boundaries between crystal grains are less well defined than the actual crystals, and have a different refractory index or optical density.\n\nIn anisotropic crystals, the refractory index or the surface structure of a transparent cut also depends on the orientation of the crystal.
20159
The chemical compositions and physical properties are identical to the natural sapphires. The tell-tale sign of synthetic sapphires is the crystalline growth lines which are usually curved due to the pulling during the accelerated crystal growth process.\n\nA version which shows an asterism (pic in source)  is called a star sapphire. Although natural sapphires can show an asterism, the shape of the star is usually somewhat irregular and sometimes indistinct. A manufactured star sapphire called the Linde Star shows a very regularly-shaped and distinct asterism because the formation process is more tightly controlled than the natural version.
750126
The best answer is C. Minerals are inorganic, have a definite homogeneous chemical structure, are solid and have a crystalline structure formed by geologic processes.
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Hardness is typically classified as calcium and magnesium.  The method I propose would demonstrate all of the dissolved solids, as well as the Ca and Mg.\n\nTake a pyrex container, fill it with drinking water, and evaporate the water off by placing it on a hot plate.  This will take awhile if you use too much water, but the 'hardness' will all remain in the container as visible evidence of the solids contained in the water.  \n\nYou can remove the deposited minerals with vinegar, or a stronger acid if you're in a hurry, just be careful.
903593
Crystal Energy et Active H\n\nSouriez à la vie et la vie vous sourira. ^---^
1113749
http://www.usoe.k12.ut.us/curr/science/sciber00/7th/classify/living/2.htm
138026
http://www.waynesthisandthat.com/crystals.htm
314284
The reason why crystals in plants vary in the plant cell is because of the plant defense. The crystals will vary according to the biome which the plant resides in. \n\n\n\noh yeah I am studying Botany
51907
The crystal structure. All minerals can be classified within 14 basic crystal lattice arrangements of the atoms in three dimensions. These 14 lattice arrangements fit within 7 larger crystal systems, allowing the classification of atomic structure of all known minerals.  To see diagrams of these go here:\nhttp://en.wikipedia.org/wiki/Crystal_structure
285911
more than 35 different types of minerals, mainly Magnesium, Sodium, Potassium, Calcium, Selenium, Chloride, Sulfur, Bromide and Manganese.
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
1144432
If  a substance is made of a single crystal(i.e. only one single crystal of large size) ,it is single crystal substance\nbut if the substance is made up of more than one crystal, then poly crystal subject
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
445892
Salt crystals can, but Bultfonteinite is usually white. So that may be what you are looking for. I found a link for you with a pic so you can see if it is what you are refering to.\nThe website also has other crystals just in case that is not it, you should be able to find it there.