20 stamps issues related to Dinosaurs & Minerals Current evidence suggests that dinosaur average size varied through the Triassic, early Jurassic, late Jurassic and Cretaceous periods.[42] Predatory theropod dinosaurs, which occupied most terrestrial carnivore niches during the Mesozoic, most often fall into the 100 to 1000 kg (220 to 2200 lb) category when sorted by estimated weight into categories based on order of magnitude, whereas recent predatory carnivoran mammals peak in the 10 to 100 kg (22 to 220 lb) category. Source: Wikipedia, the free encyclopedia A mineral is a naturally occurring chemical compound,[1] usually of crystalline form and abiogenic in origin. A mineral has one specific chemical composition, whereas a rock can be an aggregate of different minerals or mineraloids. The study of minerals is called mineralogy. Source: Wikipedia, the free encyclopedia Do not hesitate to visit our Animals category in order to have a greater choice on this subject. For lovers of nature, do not miss our selection of fauna and flores.