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Thursday January 17, 2013 (Physical Properties of Minerals Habit, Luster, Feel, Magnetism; Continue Studying Mineral Samples) Slide 2 The Launch Pad Thursday, 1/17/13 These minerals are being tested for _______. streak This mineral is about to be tested for _______. hardness These minerals are displaying different types of _______. cleavage Slide 3 Announcements Happy Hot Heads Chili Day! Slide 4 Announcements I will be available after school today until 4:45. Slide 5 Assignment Currently Open Summative or Formative? Date IssuedDate Due Date Into GradeSpeed Final Day Lab FossilsF21/91/101/18 Quiz 15S512/11 1/151/29 Video WS Geologist's Notebook What Exactly Are Minerals? F31/141/18 Slide 6 Recent Events in Science Mission Accomplished for Landsat 5 Read All About It! www.usgs.gov/newsroom/article.as p?ID=3485 Today the U.S. Geological Survey announced that Landsat 5 will be decommissioned over the coming months, bringing to a close the longest-operating Earth observing satellite mission in history. By any measure, the Landsat 5 mission has been an extraordinary success, providing unprecedented contributions to the global record of land change. The USGS has brought the aging satellite back from the brink of failure on several occasions, but the recent failure of a gyroscope has left no option but to end the mission. Now in its 29 th year of orbiting the planet, Landsat 5 has long outlived its original three- year design life. Developed by NASA and launched in 1984, Landsat 5 has orbited the planet over 150,000 times while transmitting over 2.5 million images of land surface conditions around the world. Slide 7 Minerals - The Building Blocks of Rocks Physical properties of minerals Habit Mineral habit is the shape of how a mineral tends to form. Types of mineral habits include columnar, blocky, acicular (needle-like), granular, lamellar or foliated (sheets easily split apart), botryoidal (like a bunch of grapes), fibrous, radiating, or dendritic (like a fern). Slide 8 The mineral quartz often exhibits good crystal shape Slide 9 Pyrite (fools gold) has two common crystal forms Figure 2.11 Slide 10 Figure 2.12A bladed habit Slide 11 Figure 2.12B prismatic habit Slide 12 Figure 2.12C banded habit Slide 13 Figure 2.12D botryoidal habit Slide 14 Minerals - The Building Blocks of Rocks Physical properties of minerals Luster The luster of a mineral is the way its surface reflects light. In simplest terms, minerals have a metallic or non-metallic luster. A metallic luster is a shiny, opaque appearance similar to a bright chrome bumper on an automobile. Other shiny, but somewhat translucent or transparent lusters (glassy, adamantine), along with dull, earthy, waxy, and resinous lusters, are grouped as non-metallic. Slide 15 The freshly broken sample of galena (right) displays a metallic luster, while the sample on the left is tarnished and has a submetallic luster. Slide 16 Minerals - The Building Blocks of Rocks Physical properties of minerals Feel The "feel" of a mineral can sometimes help identify it. Some minerals are greasy to the touch, others are smooth, and others have a rough feel. Diamond, which absorbs heat better than any substance, has a unique, cold feel at room temperature. talc greasy fluorite smooth feldspar rough Slide 17 Minerals - The Building Blocks of Rocks Physical properties of minerals Feel Some specimens of a particular mineral may have a rough feel since they are composed of tiny, protruding crystals, while other specimens of the same mineral have a smooth texture. Therefore, a rough feel is not necessarily an identification factor. A greasy and smooth feel, however, are inherent to all specimens of the same mineral. Fibrous minerals have a distinct, silky feel. Slide 18 Minerals - The Building Blocks of Rocks Physical properties of minerals Magnetism Several minerals react when placed within a magnetic field. Some minerals are strongly attracted to the magnet, others are weakly attracted, and one mineral is repelled. There are also several minerals that are attracted to magnetic fields only when heated.magnet The presence of iron in a mineral is responsible for the magnetic properties of minerals in virtually all cases. Slide 19 Continue Studying Mineral Samples