Mineral Hardness Ruler

Rockhounds. We can promote our hobby. What better way than to recruit our youth to carry on the hobby. Put a reminder before them all through their school days with the Mineral Hardness Ruler. Make learning a little more fun. Here's a great gift for that student in everyone's life. Every student needs a ruler for school. 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.

(Images above are not to size.)

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.

The Mineral Hardness Ruler costs $3.95 plus $1.00 shipping and handling. You may pay for your order with check draft or credit cards through PayPal

or send a check and the order form through the mail.

If you are in the Houston area, visit

Kings Gem Center at 4714 F.M. 1960 W. #107 @ Breck Rd. (281-440-9939)

on the north side of Houston. They carry rough rocks to finished jewelry and the Mineral Hardness Ruler.

© 2001-2010 Paul V. Roling All rights reserved.