6:46

Mineral Luster

24:19

Minerals with Willsey: Feldspars

17:43

Learn How to Test Mineral Hardness Using the Mohs Scale

14:47

Unboxing The Full Mohs Scale | 10 Gemstones of Hardness

30:10

How Gemstones Form From Igneous & Metamorphic Processes (12 Examples!) GEO GIRL

16:03

Minerals with Willsey: Calcite

8:40

Mineral Identification

27:59

Rock Identification with Willsey: Sandstone, Mudstone, and Shale