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Wednesday January 16, 2013. ( Physical Properties of Minerals – Streak, Hardness, and Cleavage; Begin Studying Mineral Samples ). The Launch Pad Wednesday, 1/16/13. The pictures illustrate three types of ______, which is a _________. quartz. mineral. Announcements.
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WednesdayJanuary 16, 2013 (Physical Properties of Minerals – Streak, Hardness, and Cleavage; Begin Studying Mineral Samples)
The Launch Pad Wednesday, 1/16/13 The pictures illustrate three types of ______, which is a _________. quartz mineral
Announcements Happy Appreciate a Dragon Day!
Announcements I will be available after school today until 5:00.
Recent Events in Science Neon Lights Up Exploding Stars An international team of nuclear astrophysicists has shed new light on the explosive stellar events known as novae. These dramatic explosions are driven by nuclear processes and make previously unseen stars visible for a short time. The team of scientists measured the nuclear structure of the radioactive neon produced through this process in unprecedented detail. Their findings, reported in the journal Physical Review Letters, show there is much less uncertainty in how quickly one of the key nuclear reactions will occur as well as in the final abundance of radioactive isotopes than has previously been suggested. Read All About It! www.sciencedaily.com/releases/2013/01/130115085527.htm
Minerals The Building Blocks of Rocks
Minerals - The Building Blocks of Rocks • Recall from chemistry that elements and compounds are collectively known as “substances.” • Elements bond together to form “compounds.” • Elements and compounds have a definite chemical formula. • ex.) Elements: Na is sodium and Cl is chlorine. • ex.) Compound: NaCl is sodium chloride, or common table salt. • In geology, we normally call rocky elements and compounds “minerals.” • Sodium chloride is called rock salt, or halite, when we’re discussing minerals.
Minerals - The Building Blocks of Rocks A mineral is a naturally occurring, solid chemical substance that has a characteristic chemical composition that can be expressed by chemical symbols and formulas. By comparison, a rock, which we will study later, is a mixture of minerals and does not have a specific chemical composition. Minerals range in composition from pure elements and simple salts to very complex silicates with thousands of known forms. The study of minerals is called mineralogy.
Minerals - The Building Blocks of Rocks Fluorite A mineral is naturally occurring, inorganic, solid in phase, possesses an orderly internal structure of atoms, and has a definite chemical composition. Calcite Quartz
Minerals - The Building Blocks of Rocks Physical properties of minerals Streak When you rub a mineral on a flat surface, the color of the powder left behind on the streak plate is the mineral's streak. The streak and color of some minerals are the same. For others, the streak may be quite different from the color.
Although the color of a mineral may not be very helpful in identification, the streak, which is the color of the powered mineral, can be very useful.
Minerals - The Building Blocks of Rocks Physical properties of minerals Hardness Mineral hardness is based on the ability of one natural sample of matter to scratch another. Diamond is the hardest known naturally occurring substance, whereas talc is the least hard.
Minerals - The Building Blocks of Rocks Physical properties of minerals Hardness The hardness of a material is measured against the Mohs scale by finding the hardest material that the given material can scratch, and/or the softest material that can scratch the given material. For example, if some material is scratched by apatite but not by fluorite, its hardness on the Mohs scale would fall between 4 and 5.
Mohs Scale of Hardness Figure 2.13
Minerals - The Building Blocks of Rocks Physical properties of minerals Cleavage In mineral terms, cleavage describes how a crystal breaks when subject to stress on a particular plane. If part of a crystal breaks due to stress and the broken piece retains a smooth plane or crystal shape, the mineral has cleavage. A mineral that never produces any crystallized fragments when broken off due to stress has no cleavage.