Chemistry Reference Libraries

Page 6 of about 101 Articles
2005-05-26 12:16:31

Asbestos (Greek a-, "not"; sbestos, "extinguishable") is a group of fibrous metamorphic minerals. The name is derived for its historical use in lamp wicks; the resistance of asbestos to fire has long been exploited for a variety of purposes. It was used in fabrics such as Egyptian burial cloths and Charlemagne's tablecloth, which, according to legend, he threw in a fire to clean. When...

2005-05-26 12:13:03

Augite is a mafic mineral described chemically as (Ca, Na)(Mg, Fe, Al)(Al, Si)2O6 or calcium sodium magnesium iron aluminium silicate. Structurally, it is a solid solution of the pyroxene group which also contains diopside and hedenbergite. The crystals are monoclinic and prismatic. It is found in igneous rocks such as gabbros and basalts, and in metamorphic rocks from hydrothermal vents....

2005-05-26 12:12:27

Aurichalcite is a mineral, usually found as a secondary mineral in copper and zinc deposits. Its chemical formula is (Zn,Cu)5(CO3)2(OH)6. The name probably originates from the Greek oreichalchos meaning "mountain copper".

2005-05-26 12:11:56

Autonite (Hydrated Calcium Uranyl Phosphate) is a yellow - greenish fluorescent mineral with a Hardness of 2 - 2½. Due to the high content in uranium, it is radioactive and also used as uranium ore. If the mineral dries out, it converts to meta-autunite-I, which can turn into meta-autunite-II after heating. These two subsequent minerals are very rare in nature. For scientific studies it is...

2005-05-26 12:11:19

Azurite is a carbonate mineral with chemical composition Cu3(CO3)2(OH)2, (copper carbonate hydroxide). Azurite is often found in association with the green mineral malachite as a result of the weathering and oxidation of copper sulfide minerals. The name azurite comes from the Arabic word for blue. Azurite is used in jewelry and also collected as a beautiful mineral specimen. Use as a...

2005-05-26 12:10:31

Barite (BaSO4) is a mineral consisting of barium sulfate. It is generally white or colorless, and is the main source of barium. Baryte is the British spelling. The radiating form is also sometimes refered to as Bologna Stone. Barite commonly occurs in lead-zinc veins in limestones, in hot spring deposits, and with hematite ore. It is often associated with the minerals anglesite and...

2005-05-26 12:09:54

Bauxite is a naturally occurring, heterogeneous material composed primarily of one or more aluminium hydroxide minerals, plus various mixtures of silica, iron oxide, titania, aluminosilicate, and other impurities in minor or trace amounts. The principal aluminium hydroxide minerals found in varying proportions with bauxites are gibbsite and the polymorphs boehmite and diaspore. Bauxites are...

2005-05-26 12:08:48

The mineral beryl is a beryllium aluminium cyclosilicate with the chemical formula Be3Al2(SiO3)6. The hexagonal crystals of beryl may be very small or range to several meters in size. Terminated crystals are relatively rare. Beryl exhibits conchoidal fracture, has a hardness of 7.5-8, a specific gravity of 2.63-2.80. It has a vitreous lustre and can be transparent or translucent. Its cleavage...

2005-05-26 12:07:27

Beryllium is the chemical element in the periodic table that has the symbol Be and atomic number 4. A toxic bivalent element, beryllium is a steel grey, strong, light-weight yet brittle, alkaline earth metal, that is primarily used as a hardening agent in alloys (most notably, beryllium copper). Notable characteristics Beryllium has one of the highest melting points of the light metals....

2005-05-26 12:03:03

Bornite is a sulfide mineral with chemical composition Cu5FeS4 that crystallizes in the cubic system. It has a brown to copper-red color on fresh surfaces that tarnishes to an iridescent purple surface. Its purple to bronze iridescence gives it the nickname peacock ore. Bornite is an important copper ore mineral and occurs widely in porphyry copper deposits along with more common chalcopyrite....

Word of the Day
  • A Roman unit of weight, 1⁄1728 of a pound.
  • A weight of four grains used in weighing gold and precious stones; a carat.
  • In anatomy, a formation suggesting a husk or pod.
  • The lowest unit in the Roman coinage, the twenty-fourth part of a solidus.
  • A coin of base silver of the Gothic and Lombard kings of Italy.
'Siliqua' comes from a Latin word meaning 'a pod.'