ragÂ·top (rÄgâ²tÅpâ²) n. Slang A convertible automobile. ragtop (ËrÃ¦É¡ËtÉp) n 1. (Automotive Engineering) a. a vehicle roof made of fabric, which can be folded back or removed b. (as modifier): a ragtop roadster. 2. (Automotive Engineering) (as modifier): a ragtop roadster. 3. (Automotive Engineering) a vehicle with a ragtop.
Mohs scale of mineral hardness. The mohs scale, named after Friedrich Mohs. Mohs scale of mineral hardness is named after the scientist, Friedrich Mohs, who invented a scale of hardness based on the ability of one mineral to scratch another. Rocks are made up of one or more minerals. According to the scale, Talc is the softest: it can be scratched by all other materials. Gypsum is harder: it can scratch talc but not calcite, which is even harder. The hardness of a mineral is mainly controlled by the strength of the bonding between the atoms and partly by the size of the atoms. It is a measure of the resistance of the mineral to scratching. The Mohs scale is for natural minerals. For manufactured products other measures of hardness are better.
A measure of the ease with which a smooth surface of a mineral can be scratched, or of its resistance to abrasion. In 1822 the Austrian mineralogist Friedrich Mohs devised a scale based on one mineral's ability to scratch another.He placed 10 minerals in order from softest to hardest, giving a relative hardness value of 1 to the softest mineral, and 10 to the hardest.ather, it is a method of gauging the relative hardness of a mineral. If a mineral cannot be scratched by a knife blade but can be scratched by quartz then its hardness is between 5 and 7 (stated as 5-7) on Mohs scale.