O is for obsidian Although a relative youngster in geologic terms, obsidian can change over time from glass to mineral. By Bill Langer Obsidian (ŏb-sĭd’-ē-ən) noun – a usually black or banded, hard volcanic glass formed by rapid cooling of lava that displays ...
SUBSCRIBE & FOLLOW
- MSHA's top 25 most cited standards at sand and gravel facilities in 20151630 Views
- MSHA's top 25 most cited standards at stone facilities in 20151040 Views
- MSHA issues 95 citations to seven mines during December inspections1012 Views
- Obama proposes $10-per-barrel tax on oil production694 Views
- Stockpile Reports launches bin and bunker measurement for stockpiled materials via iPhone, drone410 Views