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
Cross-polarized light photomicrograph of minerals in drill core samples from the Mesaba copper-nickel deposit, Duluth Complex, Minnesota. The number in the upper right hand corner is the drill core number.