Can this in fact be quantified, and if so translated into modern figures for easier understanding?

Not really. We have some eyewitness accounts, but they don't (and couldn't realistically) give an inventory of all that was sacked. And a great deal of damage was done in terms of cultural artifacts. How do you put a price tag on the Horses of St. Mark, one of a kind (well, four) bronze statues dating to antiquity? It would be akin to burning down the Louvre or looting the Vatican Museums. Maybe there's an actuarial number you could reach, but the price is more than that.

There is extreme difficulty in translating values of goods over such an extreme period of time. Certain goods and services are so incredibly common now that we take them for granted, but were almost unheard of back then (think something like indoor plumbing, or daily eating of large amounts of red meat like the US). The standard of living was so dramatically different as to make comparisons very, very difficult.