Unknown Coin Help Needed

Found it. It is indeed Byzantine, but it's the unusual three-quarter follis (30 nummi), denomination-letter lambda, officina-letter alpha beneath it, CON for Constantinople mintmark. Rotate the bottom pic 90 degrees clockwise to see it better. Unfortunately, the date-numerals appear to be off-flan. This coin on wildwinds of emperors Heraclius and Heraclius Constantine, is a match, while this similar type from Thessalonica mint is much easier to see. The coin is number 812 in the Sear Byzantine catalogue. As Echizento says, the "X"-shapes scratched into both sides of it are post-mint damage.

My copy of the Sear catalogue isn't older than me, but not by much, so it's values aren't much use except as a relative indication of demand. Undamaged, I'd guess a $50 to $150 coin, but you'd need to give a discount for the damage.