Collecting Rocks USGS
Trim rocks in the collection to a common size. Specimens about 3 by 4 by 2 inches are large enough to show rock features well. Other display sizes are 2 by 3 by 1 inch, or 3 by 3 by 2 inches. Ask for permission to collect rocks on private property. The owners will appreciate this courtesy on your part. Be careful when collecting rocks.