Smooth, colorful, naturally rounded river stones from your #1 landscape and building stone supplier. River jacks® are the perfect stone to accentuate your construction project. River Jacks are the ideal stone for your landscape and building needs. Our vast selection of sizes provides you with a myriad of different option. River Jacks are the ideal stone for your landscape and building needs. Our vast selection of sizes provides you with a myriad of different options. Sizes range from 3/8 Inch all the way up to our 36 Inch+ landscape boulders.