1. a dark volcanic rock composed mainly of plagioclase feldspar and pyroxene
Usage: geology

Examples

• The geologist identified the sample as tephrite based on its mineral composition.
• Tephrite formations are common in certain volcanic regions.
• The dark tephrite contrasted sharply with the lighter granite nearby.
• Students examined thin sections of tephrite under the microscope.
• The volcanic island’s coastline was composed primarily of tephrite.