Gemstone Hardness. The Mohs scale of mineral hardness was created by German mineralogist, Friedrich Mohs, in 1822 to measure the relative hardness or scratch resistance of various minerals. He based it on ten readily available minerals. As it is an ordinal scale, two minerals must be compared to decide which is harder. The scale is neither linear nor logarithmic.
AMC Black tickets are exchange items that are NOT eligible toward earning AMC Stubs rewards either at time of purchase or time of redemption. Valid seven days a week. Yellow Ticket Terms and Conditions. Not Valid in: CALIFORNIA, NEW YORK, and NEW JERSEY Present at box office only.
Black Hills Energy Credit Card Payment Online. Black Hills Energy is investor owned and also part of the Black Hills Corporation. Being in service for 125 years, Black Hills Energy now reaches more than 600,000 customers spread all across Missouri providing the required energy needs.