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What is Serpentine?
Serpentine is not the name of a single mineral. Instead it is a name used for a large group of minerals that fit this generalized formula:(X)2-3(Y)2O5(OH)4. In this formula, X will be one of the following metals: magnesium, iron, nickel, aluminum, zinc, or manganese; and, Y will be silicon, aluminum, or iron. The appropriate generalized formula is therefore as follows:(Mg,Fe,Ni,…
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Synthetic Rutile
Rutile has a very high refractive index, a strong dispersion, and an adamantine luster. These are optical properties that can produce a great gemstone, and these properties in rutile rival or exceed those of diamond. Unfortunately, natural rutile rarely has the clarity and color needed to serve as an alternative gem for diamond. However, synthetic rutile can…
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Uses of Rutile
The primary uses of rutile and titanium oxide made from rutile are: manufacturing titanium oxide pigments, manufacturing refractory ceramics, and production of titanium metal. The use of rutile to make pigments touches the lives of almost every person in the United States in many ways almost every day. When finely crushed and processed to remove…
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Rutile and Gemology
More than perhaps any other mineral, rutile has an affinity for growing as prism-shaped crystals within other minerals. Long prisms of rutile occur in many different gem minerals. Quartz, corundum (ruby and sapphire), garnet, and andalusite are some of the more familiar. Sometimes these needles are coarse and clearly visible within the gem, as in many specimens of rutilated quartz. These…
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Polymorphs and Impurities
Rutile is the most abundant natural form of TiO2. There are numerous polymorphs that include anatase and brookite. Iron (Fe+2) sometimes substitutes for titanium in some specimens of rutile. When this occurs, a valence difference between iron and titanium requires balancing – and that balance is often accomplished by substitution of niobium (Nb+5) and/or tantalum…
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Rutile Mining
Heavy mineral sands are mined in the shallow marine environment by ships that dredge up sediments, separate out the heavy mineral grains, retain the heavy minerals on-board, and discharge the lighter sediment fraction back to the bottom. Heavy mineral sands are also found on land in sedimentary deposits that accumulated at times when sea level…
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Geologic Occurrence of Rutile
Rutile occurs as an accessory mineral in plutonic igneous rocks such as granite and in deep-source igneous rocks such as peridotite and lamproite. In metamorphic rocks, rutile is a common accessory mineral in gneiss, schist and eclogite. Well-formed crystals of rutile are sometimes found in pegmatite and skarn. Rutile and a number of other metallic ore minerals are mined together from sedimentary deposits known as…
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What is Rutile?
Rutile is a titanium oxide mineral with a chemical composition of TiO2. It is found in igneous, metamorphic and sedimentary rocks throughout the world. Rutile also occurs as needle-shaped crystals in other minerals. Rutile has a high specific gravity and is often concentrated by stream and wave action in “heavy mineral sands” that exist today in both onshore and offshore deposits. Much of the…
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Ilmenite on the Moon
Apollo astronauts found ilmenite-rich basalts at multiple locations on the Moon. Most of these basalts were extremely old, forming at least 3 billion years ago. These rocks often contained over 10% titanium dioxide (TiO2). Minerals present in these rocks were mostly feldspars and pyroxenes, with ilmenite next in abundance. Some samples of lunar regolith contained significant amounts of ilmenite. It…
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Uses of Ilmenite
Ilmenite is the primary ore of titanium metal. Small amounts of titanium combined with certain metals will produce durable, high-strength, lightweight alloys. These alloys are used to manufacture a wide variety high-performance parts and tools. Examples include: aircraft parts, artificial joints for humans, and sporting equipment such as bicycle frames. About 5% of the ilmenite…