1. Plural of jaspilite; banded iron formations or metamorphic rocks composed of alternating layers of jasper and iron oxide minerals, commonly found in Precambrian shield rocks.
Usage: geology; technical; plural form

Examples

• The mining geologist identified jaspilites in the core samples from the Archean greenstone belt.
• Jaspilites are economically important as sources of iron ore in many regions.
• The alternating red and gray bands in the jaspilites indicate cyclic deposition of iron and silica.
• Precambrian jaspilites often show evidence of metamorphic recrystallization.
• The company's exploration team discovered significant jaspilite deposits in the shield region.