Small intestine. The small intestine is made up of the duodenum, jejunum, and ileum. Together with the esophagus, large intestine, and the stomach, it forms the gastrointestinal tract. In living humans, the small intestine alone measures about 6 to 7 meters long.After death, this length can increase by up to half.mall intestine. The small intestine is made up of the duodenum, jejunum, and ileum. Together with the esophagus, large intestine, and the stomach, it forms the gastrointestinal tract. In living humans, the small intestine alone measures about 6 to 7 meters long. After death, this length can increase by up to half.
Obsidian: Characteristics and Properties. Obsidian is the result of volcanic lava coming in contact with water. Often the lava pours into a lake or ocean and is cooled quickly. This process produces a glassy texture in the resulting rock.Iron and magnesium give the obsidian a dark green to black color.ften the lava pours into a lake or ocean and is cooled quickly. This process produces a glassy texture in the resulting rock. Iron and magnesium give the obsidian a dark green to black color.
Because obsidian is not comprised of mineral crystals, technically obsidian is not a true rock. It is really a congealed liquid with minor amounts of microscopic mineral crystals and rock impurities. Obsidian is relatively soft with a typical hardness of 5 to 5.5 on the mineral hardness scale. In comparison, quartz (crystallized silicon dioxide) has a hardness of 7.0. Obsidian occurs only where geologic processes create volcanoes and where the chemical composition of the magma is rich in silica.