Is it slag? How to tell the difference between obsidian and slag glass.
31:36
Rock Identification with Willsey: Volcanic Rocks (Tuff, Obsidian, Pumice)
24:02
Jade Hunting, How to "Identify" and "Test" Jade!
13:38
Collecting 101: Slag Glass! The History, Popularity, Value & How To Identify! Episode 15
9:02
World’s Sharpest Obsidian Knife
13:45
All About Fire Obsidian & More Amazing Natural Glass!
31:39
How to Tumble Leland Blue Slag Glass
18:37
Found a diamond? Identify, Test, and Verify Real Diamonds - Tips and tricks for testing
43:39