Hardness is an important and quantifiable physical characteristic of a mineral and in your effort to identify an unknown mineral, the hardness, if known, combined with other properties, can narrow your search to just a handful of possibilities. Simply scratch a smooth surface of your unknown mineral with the picks of various indicated hardness. As an example, if a No. 5 pick scratches the mineral, but a No. 4 pick does not, then your mineral hardness is 4.5. Then compare this against a table of minerals listing hardness values to aid in identifying the unknown mineral. The Deluxe Hardness Pick Set from Mineralab is unique in that, unlike other mineral hardness test tool that use minerals or crystal points, Mineralab picks are made of metals and alloys of hardness values equal to 2 through 9 on Mohs hardness scale. Because the picks are made of metal, they are easily ground to sharp points which will not break off and which can be easily sharpened. Included in the Mineralabs Deluxe Hardness Pick Set: * Four double-ended picks with eight points comprising 2 and 3, 4 and 5, 6 and 7, 8 and 9 on Mohs hardness scale. * High quality brass pinch vises. * A glass plate (hardness of about 5.5) which, when scratched, quickly distinguishes hard from soft minerals. * A second hardness plate with a hardness value of 3 5. * A white streak plate for testing a minerals streak color. * A magnet to test magnetic rocks such as magnetite and pyrrhotite. * A 100 grit polishing stone to keep the points sharp. * An attractive, mahogany-finished and compact wooden case. * Hardness Table for 300 minerals * Complete usage instructions. Other Features: * All points are stamped with the indicated hardness value, and the pick body is color coded for quickly finding the desired pick. * Hardness points can be easily and inexpensively replaced without having to replace the pick bodies. * 1 year warranty.