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Diamond and GraphiteDiamond and graphite are both crystalline forms of the element carbon. Based on this fact, one would think they would be similar in many ways. But in fact they are very different. This highlights some important facts about crystals. Both diamond and graphite have a very simple chemical composition; they are both pure carbon. Yet diamond is the hardest mineral known to man (10 on the Mohs scale), and graphite is one of the softest (less than 1 on the Mohs scale). As a result, diamond is the ultimate abrasive, whereas graphite is an excellent lubricant. Diamond is an electrical insulator while graphite is a good conductor of electricity. Diamond is usually transparent, but graphite is opaque.  Diamond and Graphite Structure
Diamond is obviously far more valuable than graphite. Graphite is so inexpensive that it is used to make pencil lead. Nonetheless graphite is as interesting a material as diamond in many ways. Graphite is the high-strength component of composites that are used to build automobiles, aircraft, high-tech golf club shafts and tennis racquets. But why is diamond so hard and graphite so soft? Also, if graphite is so soft, how can it be used as a high-tech material for golf club shafts and aircraft? The answer lies in the different atomic structures of diamond and graphite. Graphite forms in layers or sheets where the carbon atoms have strong bonds on the same plane or layer, but only weak bonds to the layer above or below. The carbon atoms in diamond, on the other hand, have strong bonds in three dimensions. In diamond, the atoms are very closely packed and each atom is connected to four other carbon atoms, giving it a very strong and rigid structure in three dimensions. In the case of graphite, only the bonds between the graphite layers are weak. This means that when the layers or sheets are rolled up into fibers, and those fibers are twisted into threads, the true strength of the bonds becomes apparent. The threads are molded into shape and held in place by a binder such as an epoxy resin. The resulting composites have some of the highest strength-to-weight ratios of any materials. The differences between diamond and graphite highlight the importance of crystal structure to the properties of a gemstone. For example, all gems that have a cubic crystal habit, where the crystal structure is completely symmetrical, have an important property in common. Cubic solids refract light in all directions at the same velocity. So even though diamond, garnet and spinel have quite different chemical compositions, they are all singly refractive because of their similar crystal structure. Other less symmetrical crystal groups are doubly refractive, including orthorhombic, monoclinic and triclinic, all of which have specific internal symmetries and axes that dictate how light bends as it enters the crystal.
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Overall Rating -> 10 After working with and polishing low-grade, rough fire-agate, only to be disappointed, this shop was nirvana. The costs of some gems might seem high, but I have easily spent the same amount rough polishing lousy material only to get a few hints of fire. If you want Fire-agates, BUY the agates you want. These are excellent specimens and are worth considering. Posted By Jim in October, 2022 Source: Bizrate Overall Rating -> 9 Great and detailed. Will be purchasing again. Posted By DJ in June, 2022 Source: Bizrate Overall Rating -> 10 My last experience was good, in fact every experience I have had with them has met my expectations or surpassed them. These are really good people to work with. Posted By Spinach in May, 2023 Source: Bizrate Overall Rating -> 10 I recently bought some stones for Christmas gifts for my family from GemSelect and was thrilled at the speed they arrived to me. The descriptions were accurate and could be verified by myself upon receiving the stones, though the only issue i had was finding exact stones i wanted. The sorting system is fanastically detailed, but often seems to trim more results than expected when i was selecting things to look by. They arrived safely and all together, as described per my purchase order and i could not be more satisfied. There aren't many that are looking to buy loose stones like this, but it really gets the job done. Posted By Lev in December, 2022 Source: Bizrate Overall Rating -> 10 I was looking for Star Sapphires, not blue sapphires. In the past, I boughtBlack Star, I love it! Today, I ordered aPurple Star. I gave rings made with the gems. Posted By Sunny in June, 2022 Source: Bizrate Overall Rating -> 10 It’s always awesome and easy to do Posted By Dustyrose in July, 2022 Source: Bizrate Overall Rating -> 10 Bought my first set of gemstones of gemselect to start off my collection. Everything is what it says it is, 100% legit. They even send u a pamphlet for every gem you order even the $1 ones lol. Good store. Posted By SuperBee in March, 2023 Source: Bizrate Related Articles Sapphire Info Sapphire Information - The heavenly blue gemstone of royalty ... Emerald Info Emerald Information - Vivid green gemstones of unequaled quality ... Star Sapphire Info Star Sapphire Gemstone Information - GemSelect ... Zircon Info Zircon Information - A gemstone as old as the earth itself ... Gemstone Clarity and Cut Clarity and Cut - Gemstone Information - GemSelect ... Refractive Index Chart Refractive Index Chart - What does it mean and how do I use it? ... Specific Gravity Chart Specific Gravity Chart - Gemstone Information - GemSelect ... Jacob the Jeweler Jacob the Jeweler ... Jet Black Gems Jet Black Gems ... Cubic Zirconia Cubic Zirconia Info ... |
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Gems are always measured in Millimeter (mm) Dimensions are given as; Select gems by size, not by weight! Note: 1ct = 0.2g  |
