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.
Reflected light, crossed Nicols, immersion in cedar oil. Microcrystalline aggregates in the sample: (a) NV4-Hematite (white, red internal reflections), magnetite (gray); (b) NV5-Hematite (white, red internal reflections), magnetite (gray); (c) NV6-Magnetite (gray), hematite (white, red internal reflections); (d) NV7-Hematite (white, red internal reflections), magnetite (gray).
