Scolecite was first described from Kaiserstuhl in Baden-Württemberg in 1813. Divergent groups of prismatic crystals are found in the basalt of Berufjörður near Djúpivogur, Suður-Múlasýsla, Iceland and in the Deccan Traps near Pune in India; hence the synonym poonahlite for this species. Other occurrences include Riverside County, California; Skye, Scotland and Santa Catarina, Brazil.
There is no type locality. Most of the world's finest scolecite specimens are found in the Tertiary Deccan Basalt near Nasik, Pune, in the state of Maharashtra, India. The quarries in the Nasik region produce large, colorless sprays of well terminated coarse scolecite crystals that are commonly twinned on {100} to form V-shaped terminations with V-shaped striations on {010}. The scolecite is commonly found alone or on stilbite and is covered with laumontite or colorless, pale green or white fluorapophyllite. It is also found in the region as massive radiating material with powellite, and in cavities in basalt as colorless, flattened crystals in radiating sprays on blocky green apophyllite covered by tiny, thin, colorless apophyllite plates.
Scolecite has been reported from many other localities, including Antarctica, Australia, Austria, Brazil, Bulgaria, Canada, Chile, Czechoslovakia, Ethiopia, Faroe Islands, France, Germany, Greenland, Hungary, Iceland, Italy, Japan, Mexico, Mozambique, Nicaragua, Peru, Poland, South Africa, Sweden, Switzerland, Taiwan, United Kingdom, United States and Yugoslavia.