Jade Yoga Cork Block Jade Cork Yoga Blocks are made with cork harvested sustainably in Portugal from the bark of native cork trees, a rapidly renewable resource Cork provides comfort, strength, stability and firm support for your yoga practice. Cork is naturally antimicrobial and water-resistant. Available in Small (3" x 4.75" x 9") and Large (4" x 6" x 9"). Jade Cork Yoga Blocks are non-slip, to help you find stability in your poses.