An official website of the United States government. Here's how you knowHere's how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock () or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Latest Earthquake | Chat Share
Diabase is a mafic (meaning high in magnesium and iron), igneous rock that usually forms below the Earth’s surface. This particular one has large amounts of augite and labradorite minerals, and comes from the Lucke Quarry, which is southeast of Leesburg, VA.