Jaspillite (or jaspilite), also called itabirite or jasper taconite, is a chemical rock formed similar to chert, but is generally quite iron-rich. Jaspillite is typically a banded mixture of hematite and quartz common in the banded iron formation rocks of Proterozoic and Archaean age in the Canadian Shield.
![](http://upload.wikimedia.org/wikipedia/commons/thumb/1/11/BIF_%28jaspilite_meta-BIF%2C_Paleoproterozoic_Minas_Gerais.jpg/220px-BIF_%28jaspilite_meta-BIF%2C_Paleoproterozoic_Minas_Gerais.jpg)
Jaspillite is also formed as exhalative chemical sediments in certain lead-zinc ore deposits, and as a hydrothermal alteration facies around submarine volcanism. It is used as a gemstone.[1]
References
edit- ^ Sinkankas, John (1959). Gemstones of North America. Vol. 1. p. 345.