Note that the Orientation Slice is cut precisely to the (100) before the crystal is rotated and cut at either +.25 degrees and toward the flat, or â.25 degrees and away from the flat (as described in Figure 3).
The era was called the Dark Ages also because we don't have a lot of written sources from that time period, especially from the early part of the dark ages (500 to 800 CE).
The Middle Ages are a time period in European history. They started around the year 476 CE when the Western Roman Empire ended, and continued until around the time Christopher Columbus discovered the New World in 1492. The 'Middle Ages' are called this because it is the time between the fall of Imperial Rome and the beginning of the Early modern Europe. This period of time is also known as the Medieval Age, the Dark Ages, or the Age of Faith (because of the rise of Christianity and Islam). When used narrowly, the term Dark Ages refer only to very early period, from 476 to 800 (when Charlemagne became king).