A guide to the geology of one of the most scenic regions of the Central Appalachian Mountains 65 miles west of the Washington D.C. Beltway.
Intended for students, teachers, hikers, motorists and the armchair geologist alike: A guide to a classic area of Appalachian geology in the eastern Valley and Ridge Province. The book combines descriptions of the landscapes, rocks, minerals, fossils, stratigraphy, folds and faults with basic principles of geology.
Useful for enjoying, planning trips, and as a source of information for writing and teaching about the geology of this beautiful region of the Appalachians mainly in the George Washington National Forest.
Written by geologist Bill Melson, geologist emeritus, National Museum of Natural history, Smithsonian Institution, fellow of the Geological Society of America and the American Mineralogical Society, and instructor for geology tours and courses for the Smithsonian Resident Associates and the Potomac Appalachian Trail Club and other organizations
The Mineral Hardness Ruler is a stimulating visual aid, educates in one phase of mineralogy, and provides the standard ruler measurement scales needed in classes.
Rockhounds, mineral enthusiasts, students, teachers, geologists, and any one interested in rocks and minerals will find the Mineral Hardness Ruler a handy visual aid for quick information on mineral hardness.
The two-sided, flexible, glossy, vinyl ruler consists of five scales: three measurement scales and two mineral hardness scales. The measurement scales are in standard ruler measurements of tenths of inches, sixteenths of inches, and millimeters. Mohs' relative hardness numbers are integrated into the inch scales, while a separate scale exists for an absolute mineral hardness scale by Rosiwal.
On one side of the ruler are pictures of the ten common minerals, in full color, selected by Mohs for his relative hardness scale. On the reverse side of the ruler are six common items with their relative hardnesses. These items, along with known minerals, can be used as a handy field kit to test the relative hardness of an unknown mineral.
Hardness is one property of a mineral that can be used to distinguish among similar minerals. A given mineral can scratch any other mineral of the same or softer hardness. Over a hundred years ago, the German mineralogist Frederick Mohs devised the relative hardness scale that has found favor with mineralogists for over a century. Others, such as Rosiwal, formed absolute hardness scales using the same minerals as Mohs. For example, diamond, the hardest substance in Nature is not twice as hard as apatite, 10 versus 5, but over twenty thousand times as hard, 140,000 versus 6.5.
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