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 term Dark Ages was coined by an Italian scholar named Francesco Petrarch. Petrarch, who lived from 1304 to 1374, used this label to describe what he perceived as a lack of quality in the Latin literature of his day.