- Edit 2Before modification by Joel at 11/03/2013 05:14:01 PM
If, in the letters, one sees the digamma, which looks like an F (because it's the origin of the Latin letter F). It wasn't used in writing but it was used, solely and exclusively, to represent the number 6. Similarly, qoppa (which looked like a Q) represents only 90, and sanpi (which looked just weird) represented 900. If you add those three letters to the 24 letters of the Greek alphabet, you get 27, or 3 sets of 9s, which were used for 1-9, 10-90 and 100-900, respectively.
On a 20-sided die, if the letters represent numbers, you wouldn't get to qoppa or sanpi, but you would get digamma.
What you say here is pretty much the rationale I arrived at by comparing online listings of Greek numbers to the characters visible on the die: It could not display all 27 Greek numerical glyphs, but could display Greek numerals through 20. Unfortunately I only have the two pics from the CNet article, which only shows ten of the dies faces. I can identify all but one or two of those shown (depending on whether the possible digamma IS the digamma.) Both kappa and rho are present, so my current working theory is that it may have been a quasi-d100 rolled twice and added to return a result 0-200.
The digamma MAY be present, I cannot be sure; if so, based on the orientation of the other numbers it is turned on its side. It could also be the hieratic glyph for 10, which would further complicate things because an adjacent face has an I. Also, if I understood Wikipedia correctly, any die prior to the Medieval era would, as you said, represent the digamma as F, not ϛ, which would raise the possiblity this is a Byzantine die found in Ptolemaic ruins (or, y'know, an archeologists practical joke/fraud.) There is also an additional glyph I do not recognize between B, E and Θ; I thought it might be an uppercase qoppa or sanpi, but it does not look like any examples I have seen of those.
I see the Greek glyphs for 2, 3, 4, 5, 7, 8, 9, 10, 20, 100 and MAYBE 6, then another I do not recognize.