A special form of peridotite called kimberlite is, with related lamproite, the world's only primary source of diamonds (see Kimberlites and lamproites, right). But other peridotites are major sources of nickel and chromium minerals, platinum and talc, and chrysotile asbestos, too. In warm, humid places, peridotite has weathered to soils rich in iron, nickel, cobalt and chromium, which may one day be exploited as ores on a large scale.