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.
It provides an introduction to their genesis, details of their structural characteristics, and a multitude of macro and micro photographs. It's a stating-point for some of the current theories of their formation, and contains references to more in-depth studies.
No other variety of material offers so many combinations of patterns and spectral colors. Sit back and now an enjoy the complexity and beauty locked within these stones."(Taken from the rear cover)
This is a 9" x 12" softcover book with 240 glossy color pages and over 1000 photos and diagrams. Agate and jasper structures are shown in macro-photography, micro-photography, and in representative thin-sections. The books weighs just under 3 lb. (1.5 kg.), so international shipping is expensive.
The first section explains the genesis of agates and provides diagrams of their internal structure with thin-section examples. This is followed by several sections showing example photographs of fortification agates, plume agates, moss & tube agates, sagenitic agates, and other varieties. Limited locale information is provided.
The next section explains the formation of jasper with examples of structural characteristics again using several thin-sections. It discusses much of the market misnaming of a host of materials as jaspers. This is followed by many sections with photographic examples of generic jaspers, brecciated jaspers, orbicular jaspers, and scenic jaspers.
Finally there is a short section with a discussion of rhyolites and their confusion with jaspers. Followed by an even shorter section on fossilized materials. Both of these sections have abundant photo-examples.
Our review: "The youngest child may just enjoy playing with the stickers. An older child can read the descriptions and will learn about rocks, minerals, and fossils."
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