Pages authored by Dr. Nelson Shaffer:

1. Rocks and Minerals / Armored Mudballs
   Following the torrential rains of June 2008, this group of small armored mud balls was found in a ravine in northeastern Monroe County, Indiana. They consist of a core of red clay armored by an assortment of granules and pebbles from 2 to 15 millimeters in diameter. The mud balls themselves are 3 to 6 centimeters in diameter.
2. Rocks and Minerals / Calcite
   Indiana's best-known and most abundant mineral is calcite (fig. 1). It is composed of calcium (Ca), carbon (C), and oxygen (O); its formula is CaCO3, with the atoms arranged in alternating layers of small calcium atoms and bicarbonate (CO3) layers (fig. 1). Calcite is the major mineral in the Indiana state stone, limestone.
3. Rocks and Minerals / Gypsum
   Deep below the rugged surface of Indiana's Martin County people work in two underground mines to extract and process an unusual mineral resource - gypsum. Gypsum (CaSO4*2H2O) is a soft, water soluble mineral that is processed to make critical building materials especially wallboard.
4. Rocks and Minerals / Meteorites
   Meteorites are rocks that fall to Earth from outer space. They have fascinated mankind since the beginning of time. They are scientifically valuable objects that help geologists understand the origins of planets and the processes that shape the Earth. Meteorites are rare and they exhibit special features that differentiate them from Earth rocks.
5. Rocks and Minerals / Pyrite
   Pyrite is a pretty mineral (Fig. 1) common to Indiana, but it also has a dark side. It is composed of iron (Fe) and Sulfur (S) with a chemical formula of FeS2. Atoms are arranged in an isometric crystal structure (Fig. 2) that makes cubic crystals.
6. Rocks and Minerals / Quartz
   Quartz is one of the Earth's most abundant minerals. It has a simple chemical formula (SiO2) but is very stable and resistant retaining its identity even billions of years after its formation, extreme weathering and, transport. Quartz (Fig. 1) has always played a large role in human technology.