CopperCopper is one of the most famous and useful metals, and has been important since ancient civilizations for ornaments and coinage. Its complex crystals can be beautifully formed in odd and unique masterpieces that are treasured by collectors.
Copper may have impurities, but is commonly in a fairly pure state. Native copper is found only in small quantities throughout the world, but there are a few areas that are rich in findings, such as the Keweenaw Peninsula in Michigan. Well crystallized specimens are not common, and are very much sought after. The interlocking Copper and Silver masses that are commonly found in the Keweenaw Peninsula are known as "Halfbreeds". Some Copper on the mineral market has been cleaned and shined using various solvents. These forms are Copper can easily be spotted as their copper-red color is almost artificial looking in its fleshy hue. http://www.minerals.net/mineral/copper.aspx DiamondDiamond has many unequaled qualities and is very unique among minerals. It is the hardest known substance, it is the greatest conductor of heat, it has the highest melting point of any substance (7362° F or 4090° C), and it has the highest refractive index of any natural mineral. Diamond is number 10 on the Mohs scale, and is 40 times harder than Corundum, which is number 9 on the Moh's scale. It also has the most dense atomical configuration of any mineral, and is transparent over the greatest number of wavelengths. Because of heat conduction, Diamonds are cold to the feel at or below room temperature. When heated, a Diamond will remain hot long after the heat source is removed.
The luster of Diamond is excellent. Diamond exhibits great "fire" and brilliance, which gives it a shiny, freshly polished look. Rough Diamonds exhibit a greasy luster, but proper cutting give them a powerful adamantine luster. Only synthetic substances and a few minor gemstones can reach or excel the refractive index of Diamonds. The hardness and refractive index may slightly vary among Diamond specimens. Bort and Carbonado exhibit a slightly lower hardness than other Diamonds, and lack cleavage. Lonsdaleite (also known as Hexagonal Diamond), is a type of Diamond found with meteorites and is of extraterrestrial origin. It is scientifically a different mineral than Diamond, and believed to have formed when meteoric Graphite fell to earth. When this happened, great heat and stress transformed the Graphite into Diamond, but it retained Graphite's hexagonal crystal lattice. http://www.minerals.net/mineral/diamond.aspx GoldGold is one of the most popular and well-known minerals, known for its value and special properties since the earliest of time. Most of the natural Gold specimens that have been found since early times have been smelted for production. Nice specimens, therefore, are regarded very highly, and are worth much more than the standard gold value. Only recently have more specimens been available to collectors, as more miners have been saving some of the larger pieces for the collectors market.
Gold in its natural mineral form almost always has traces of silver, and may also contain traces of copper and iron. A Gold nugget is usually 70 to 95 percent gold, and the remainder mostly silver. The color of pure Gold is bright golden yellow, but the greater the silver content, the whiter its color is. Much of the gold mined is actually from gold ore rather then actual Gold specimens. The ore is often brown, iron-stained rock or massive white Quartz, and usually contains only minute traces of gold. To extract the gold, the ore is crushed, then the gold is separated from the ore by various methods. Gold nuggets, a popular form of Gold with collectors, are formed when erosion causes a large piece of Gold to separate from its mother rock, and then gets carried into a stream or river. The flowing water tumbles the Gold, giving it its distinct rounded shape. The Gold eventually settles at the bottom of the water, and due to its heaviness remains there. Other nuggets also get caught in the same area, forming a placer deposit. Gold is one of the heaviest minerals. When pure, it has a specific gravity of 19.3. Due to its weight, it can be panned because the Gold sinks to the bottom. In addition, it can be easily separated from other substances due to the weight differences. Gold is also the mostmalleable and ductile substance known. It can be flattened out to less than .00001 of an inch (less than .000065 cm), and a 1 oz. (28 gram) mass can stretch out to a distance of over 50 miles (75 kilometers). Gold is also one of the most resistant metals. It won't tarnish, discolor, crumble, or be affected by most solvents. This adds on to the uniqueness and allure of this mineral. Gold is usually associated with Pyrite and other sulfides, and sometimes may not be noticed because of the association with these resembling minerals. In certain localities, minerals that contain these sulfides are heated high enough for the sulfides to dissolve, enabling the Gold to remain intact on the matrix. Such Gold is known as "Roasted Gold", and is occasionally sold to collectors. http://www.minerals.net/mineral/gold.aspx GraphiteGraphite is rather common, but fine crystals are rare. Most Graphite mining areas produce enormous quantities from a single or several large Graphite veins. Graphite has the samechemical composition as the mineral Diamond, but the atomic structure of Graphite and Diamond is entirely different. This causes almost opposite characteristics in their physical properties.
Much care should be given to Graphite specimens, especially thin crystals, which are fragile. It is very hard to wash crystals as they peel off and get ruined. Graphite will also smudge on its surface, and can get worn out if it is moved around too much. Graphite also smudges the hand if handled, and will smudge a paper or cardboard box if it is stored in one. http://www.minerals.net/mineral/graphite.aspx SilverSilver is one of the most famous precious metals, and has been used for ornamental purposes since the earliest of times. Most silver is extracted from silver ores, but considerable amounts are mined from Native Silver. Silver can be found pure, but is usually mixed with small amounts of gold, arsenic, and antimony. A natural alloy of gold and silver is known as Electrum, and is usually classified as a variety of Gold.
Silver is a very resistant mineral. It does not dissolve in most solvents, and won't react to oxygen or water. However, it has a detrimental reaction to sulfur and sulfides, which causes it to tarnish on exposed surfaces. Hydrogen sulfide (H2S) is found in the atmosphere in small quantities, and when silver is exposed to normal air it reacts to the hydrogen sulfide, causing the tarnish. Egg yolks, which contain sulfur compounds, should be kept away from silver. Several chemical coats are available to protect it from tarnish, and certain polishes remove tarnish. http://www.minerals.net/mineral/silver.aspx SulfurPure Sulfur is bright yellow. The color may be altered if impurities are present. Clay and selenium impurities, as well as volcanic mixtures in sulfur can cause it to be slightly red, green, brown, or gray. Sulfur often occurs in petroleum deposits, where it is found coated with greasy black petroleum.
Sulfur is soft, light in weight, and very brittle. Care must be exercised when handling and storing specimens. When kept moist or not allowed to dry when wet, hydrogen will mix with the Sulfur, forming hydrogen sulfide (H2S), which causes the deterioration of a specimen. To prevent this, Sulfur should not be stored under humid conditions. It is best not to wash Sulfur specimens, as warm water can dissolve it. Sulfur also has the tendency to crack when exposed to mild heat, including body heat. It should be handled as little as possible, and kept out of light to avoid cracking. The earthy, massive, specimens usually come from volcanic sulfur springs, and have small, bubbly holes throughout. These specimens usually have a greasy feel, and exhibit a strong"rotten-egg" odor. Much of the fine natural Sulfur crystals are destroyed by mining operations. In mining, underground Sulfur deposits are flooded with hot water, causing the Sulfur to melt into a brine. The brine is pumped to the surface, where the water is evaporated and the sulfur recovered. Such mining operations destroy all specimens. Sulfur crystallizes in the orthorhombic system, but an uncommon monoclinic form of sulfur also exists. This monoclinic form is scientifically considered a different mineral than Sulfur, and is scientific name is Rosickyite. http://www.minerals.net/mineral/sulfur.aspx |
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