â¢ SULTAN (noun). The noun SULTAN has 1 sense: 1. the ruler of a Muslim country (especially of the former Ottoman Empire). Familiarity information: SULTAN used as a noun is very rare. SULTAN (noun). The noun SULTAN has 1 sense: 1. the ruler of a Muslim country (especially of the former Ottoman Empire). Familiarity information: SULTAN used as a noun is very rare.
Fossils also form from molds and casts. If an organism completely dissolves in sedimentary rock, it can leave an impression of its exterior in the rock, called an external mold. If that mold gets filled with other minerals, it becomes a cast. An internal mold forms when sediments or minerals fill the internal cavity, such as a shell or skull, of an organism, and the remains dissolve. Organic remnants. In recent years, researchers have discovered that some fossils aren't just made of minerals.
Jupiterimages/Photos.com/Getty Images. Limestones are a class of sedimentary rocks composed of the same mineral, calcite, which is made from calcium carbonate, or CaCO3. Despite this similarity in composition, however, not all limestone rocks are the same. Chalk is actually a special form of limestone that exhibits some differences from other rocks in the same class.