Heavy duty 3/4'' plain black nylon loupe lanyard with a quick release buckle and a split ring. This lanyard may be used for any purpose but we've had it custom manufactured specifically for use with the BelOMO loupe.
Important: We offer this lanyard for no additional charge when you buy the combo package of the BelOMO loupe with attached lanyard. Attaching the lanyard requires a screw to be removed so let us do it. We've been doing it for years and you save money!
Use the split ring on loupes with a mounting hook. To use the lanyard with a BelOMO loupe remove one screw on the support shaft of your BelOMO loupe, swivel the frame out of the way and slide the end over the support shaft then install the screw again. Don't use the split ring to attach the lanyard to the loupe. (We suggest that you purchase the loupe with the lanyard already installed.)
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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