Rock Tumbling for Beginners: Determining a Rock’s Hardness

When you tumble rocks, you should always put rocks of similar hardness together. Mixing hard and soft rocks will bring discouraging results. So, a beginning rock tumbling hobbyist needs to know how to determine a rock’s hardness. 

In the video, Jim refers to the Mohs Hardness Scale and posts a chart. Here’s a link to the chart, from the U.S. National Park Service: https://www.nps.gov/articles/mohs-hardness-scale.htm