Selecting Rough Rocks for Tumbling

Selecting rough rocks for tumbling can be a bit daunting if you are new to tumbling! So we have written this short guide in the hope that it will enlighten you to what to consider.

Selecting Rough Rocks for Tumbling

The MOHS scale is a table of the “hardness” of rocks and minerals and you should always try to tumble rocks of a similar hardness together. Let us explain, if you were to tumble say Lapis Lazuli which has a hardness rating of 4 on the MOHS scale with some Jasper which as a hardness rating of 7 on the MOHS scale. You would be quite disappointed to find that your Lapis Lazuli would have eroded much more than the Jasper after the first 7 days of tumbling.

The MOHS Scale and Selecting Rough Rocks for Tumbling

The reason for this is that the silicone carbide grit and the Jasper are both much harder than the Lapis Lazuli, so it follows that it will erode much quicker.

So if you say filled a tumbler barrel with all Jaspers or a mix of Jasper and other rocks of similar hardness they would erode evenly during the tumbling process.

To help you all our Rough Rocks for Tumbling on our web site have the MOHS hardness rating in the description.

From experience we find that you can tumble rocks with a MOHS rating of 6 to 7 together without problems. Similarly rocks in the 4 to 5 range also work well together.

So there you are a quick guide to Selecting Rough Rocks for Tumbling for those who are new to Rock Tumbling.