Selenite (mineral) was filled with mineral-rich water that drove the crystals' growth. The largest of those crystals weighs 55 tons, is long, and is over 500,000 years old. Gypsum occurs on every continent and is the most common of all the sulfate minerals. Gypsum is formed as an evaporative mineral, frequently found in alkaline lake muds, clay beds, evaporated seas, salt flats, salt springs, and caves. It is frequently found in conjunction with other minerals such as, copper ores, sulfur and sulfides, silver, iron ores, coal, calcite, dolomite, limestone, and opal. Gypsum has been dated to almost every geologic age since the
Interlanguage fossilization does motivation to achieve native-like competence diminish? The concept of fossilization in SLA research is so intrinsically related to interlanguage that Selinker considers it to be a fundamental phenomenon of all SLA and not just to adult learners. Fossilization has received such wide recognition that it has been entered in the "Random House Dictionary of the English Language" (1987). Selinker's concept of fossilization is similar to that of Nemser, Tarone, and Sridhar, all of whom attempted to explore the causes of fossilization in second language learners' interlanguage. Fossilization has attracted considerable interest among researchers and has engendered significant differences of