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.
At least one carrier â Continental â now offers travelers the ability to lock in a fare for 72 hours for a fee of $5 or for seven days from $9, depending on the itinerary, with no obligation to buy. Travelers can purchase the ticket at any time before the so-called FareLock expires. Look for sales at the last minute.