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).
This decline persisted throughout the period of time sometimes called the Dark Ages (also called Late Antiquity or the Early Middle Ages), from the fall of Rome to about the year 1000, with a brief hiatus during the flowering of the Carolingian court established by Charlemagne.