Mosaic Monday Fun Fact

MOSAIC MONDAY 

Fun Fact:

"Before man figured out how to craft glass, nature was already making it. When lightning strikes sand, the heat sometimes fuses the sand into long, slender glass tubes called fulgurites. The intense heat of a volcanic eruption sometimes fuses rocks and sand into a glass called obsidian. In early times, people shaped obsidian into knives, arrowheads, jewelry, and money."

Source: Bottles Up