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 Dark Ages as a term has undergone many evolutions; its definition depends on who is defining it. Indeed, modern historians no longer use the term because of its negative connotation. Generally, the Dark Ages referred to the period of time ushered in by the fall of the Western Roman Empire.