thumb|Greensand (glauconitic sandstone) alt=This image shows a rock and the occurrence of glauconitic siltstone in the Serra da Saudade ridge, in the Alto Paranaíba region, Minas Gerais state, Brazil.|thumb|Occurrence of glauconitic siltstone in the Serra da Saudade ridge, in the Alto Paranaíba region, [[Minas Gerais, Brazil]] Greensand or green sand is a sand or sandstone which has a greenish color. This term is specifically applied to shallow marine sediment that contains noticeable quantities of rounded greenish grains. These grains are called glauconies and consist of a mixture of mixed-la
thumb|Greensand (glauconitic sandstone) alt=This image shows a rock and the occurrence of glauconitic siltstone in the Serra da Saudade ridge, in the Alto Paranaíba region, Minas Gerais state, Brazil.|thumb|Occurrence of glauconitic siltstone in the Serra da Saudade ridge, in the Alto Paranaíba region, [[Minas Gerais, Brazil]] Greensand or green sand is a sand or sandstone which has a greenish color. This term is specifically applied to shallow marine sediment that contains noticeable quantities of rounded greenish grains. These grains are called glauconies and consist of a mixture of mixed-layer clay minerals, such as smectite and glauconite. Greensand is also loosely applied to any glauconitic sediment.
==Formation== Greensand forms in anoxic marine environments that are rich in organic detritus and low in sedimentary input. Having accumulated in marine environments, greensands can be fossil-rich, such as in the late-Cretaceous deposits of New Jersey, United States.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).