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.
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."
Estwing's Cushion Grip drilling chisel. Foam cushion grip to reduce impact. Heavy duty wide Hard Cap minimizes chips from flying off the chisel head and provides a wider head to help protect the hands from missed blows. Even has a centering target! This Estwing rock chisel has a bull or pointed edge. The tip is square, 4 sided, with each side tapering to a point. The bull point chisel for drilling into rock. Use it to gain accuracy when trying to remove specimens from the country rock. Maximum design hammer head weight: 3 lbs.
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