This is a Jasper called blood stone or dragons blood. There are many types of Jasper's out there. Please look at the photos provided. You will get something along the lines of any of those stones. If you want to pick individual stones you can do that on the retail web site www.cameojewelrysupply.com Generally thought to be formed from volcanic ash and sediment often producing odd colors and patterns where various minerals have permeated. Usually iron would be the red color. This stone is mostly green with red mottling. Note that there are also often little white veins or little crevices of a softer mineral throughout the stone. Fair amount of variation from stone to stone. I have included a photo of what the raw stone looks like before it is cut and polished. The stone is said to promote strength, courage, and purpose to help face difficulties and to heal repressed emotional issues. Size is listed in the product title in millimeters (mm)