any sedimentary rock containing various amounts of solid organic material that yields petroleum products, along with a variety of solid by-products, when subjected to pyrolysis—a treatment that consists of heating the rock to above 300 °C (about 575 °F) in the absence of oxygen, kollakas kuni peaaegu must settekivim, mis sisaldab peamiselt veekogude madalamatest organismidest pärinevat vesinikurikast orgaanilist ainet kerogeeni. Termiliselt lagunedes annab kerogeen suure õlisaagise. Peale orgaanilise aine sisaldab põlevkivi mineraalaineid ja vett; kütteväärtus 1200-4800 kcal/kg., kivim, mille orgaanilise aine õliandvus on >20%