Lithology 7. The naming of a lithology is based on the rock type. The three major rock types are sedimentary, igneous, metamorphic. Sedimentary rocks are further classified by whether they are siliciclastic or carbonate. Siliciclastic sedimentary rocks are then subcategorized based on their grain size distribution and the relative proportions of quartz, feldspar, and lithic (rock) fragments. Carbonate rocks are classified with the Dunham or Folk classification schemes according to the constituents of the carbonate rock. The name of an igneous rock requires information on crystal size and mineralogy. This classification can often be performed with a QAPF diagram. Metamorphic rock
Substance use disorder Substance use disorder A substance use disorder (SUD), also known as a drug use disorder, is a medical condition in which the use of one or more substances leads to a clinically significant impairment or distress. Substance use disorders are characterized by an array of mental, physical, and behavioral symptoms that may cause problems related to loss of control, strain to one's interpersonal life, hazardous use, tolerance, and withdrawal. Drug classes that are involved in SUD include alcohol, opioids, stimulants, tobacco, hallucinogens, phencyclidine, inhalants, and sedatives. Worldwide 275 million people were estimated to have used an illicit drug in 2016.