Concrete Stone Veneer Mold 201/2 Concrete Stone Venner Mold Globmarble supplies professional grade casting molds which reproduce the structure and relief of natural stone to the smallest details. Molds made of two-component polyurethane or silicone rubber proved their high quality and durability. GlobMarble molds are designed to produce many parts and will last you many years by using a little common sense and incorporating a maintenance plan. HOW TO MAKE CONCRETE STONE: Apply release (can be used liquid soap). Mix concrete per instruction, add colors, vibrate the mold lightly to remove an air bubbles, remove the stone in 24 hours.