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).
To many historians the fall of the Roman Empire has always been viewed as the end of the ancient world and the onset of the Middle Ages, often improperly called the Dark Ages, despite Petrarchâs assertion.