When Eli Whitney invented the cotton gin, slavery in the United States was in a large decline, do to the inherent unprofitable nature of the cotton/plantation/slave economy in â¦ the southern states.
Jasper is a cryptocrystalline variety of the mineral Quartz (SiO 2). Quartz is the most abundant single mineral on earth. It makes up about 12% of the earth's crust, occurring in a wide variety of igneous, metamorphic and sedimentary rocks.
Pegmatite containing lepidolite, tourmaline, and quartz from the White Elephant Mine in the Black Hills, South Dakota. A pegmatite is a holocrystalline, intrusive igneous rock composed of interlocking phaneritic crystals usually larger than 2.5 cm in size; such rocks are referred to as pegmatitic.Most pegmatites are composed of quartz, feldspar and mica, having a similar basic composition as granite.rystal size is the most striking feature of pegmatites, with crystals usually over 5 cm in size. Individual crystals over 10 metres across have been found, and many of the world's largest crystals were found within pegmatites. These include, spodumene, microcline, beryl, and tourmaline.