These are the least abundant of the three main types of meteorites and only account for about 2% of all known specimens to date. Most stony-iron meteorites are composed of almost equal amounts of nickel-iron and stone and then are further divided into two groups: Pallasites and Mesosiderites. These stony-iron meteorites are believed to have formed inside of a larger parent bodies where the core and mantle meet.
Pallasites are easily the most visually appealing of all meteorites and high sought after by collectors and jewelers alike. These objects consist of a nickel-iron matric that is packed full of olivine crystals. These crystals vary in shape and size from a few millimeters up to multiple centimeters and can be seen in colors ranging from deep oranges to light greens. Purer specimens with an emerald-green color even have their own name coined, gemstone peridots. Once these objects are cut and etched, the metallic shine of the metal alloys will appear next to translucent "gems" which give them an out of this world beauty.
Mesosiderites are the smaller of the two stony-iron groups and contain both nickel-iron and silicates that show a very attractive, high-contrast silver and black matrix when polished. The name mesosiderite is derived from the Greek words "half" and "iron." Fewer than 100 of all catalogued meteorites are mesosiderites.