Interesting word just previous: nummularius ("money changer"). Checking the etymology online, I find nummus (coin, money) + -ulus (diminutive suffix, i.e. "small coin" or "small amount of money") + -arius (denoting "dealer, agent"). Embedded in the word nummularius is the word nummulus which I was able to find used by Cicero in a letter to Atticus (8.13.2) written 49 BC, describing attitudes of both town and country folk amid the civil strife: Nihil aliud curant, nisi agros, nisi villulas, nisi nummulos suos ("They care for nothing except their fields, their little villas, their little coins"). One published translation reads "They really think of nothing except their fields and their bits of farms and investments."
In late 5th - early 6th c. Carthage, under the Vandals, they minted coins of 4 nummi with the mark of value on the reverse : N(ummi) / IIII. (1.34 g, not my coin): Is this the only ancient coin on which the word nummus can be read? These coins are probably contemporaneous with the Anastasian reform.
Here are three other Vandalic coins with "N", apparently for nummi, civic 42 nummi (NXLII) of Carthage and silver 500 nummi (DN) of Gelimer and Gunthamund (images courtesy CNG).
I had no idea that the N stood for nummi on these coins. By the way, I think there may actually have been a one nummus coin sometime early in the Byzantine period, maybe Anastasios or Justinian, though I don't recall ever actually seeing one.
Here's a Nummus struck under Emperor Leo, as well as a Decanummium (10 Nummi) wich was struck under Ostrogoth king Theodoric.
I posted this coin twice before. It's now in my old folders. I guess it's nearly 10 mm. with a weight of nearly 1 g. It's a tiny coin.
I don't know how many of these one nummus coins were minted but I'll bet a high percentage were lost and never recovered in ancient or modern times.
Seeing this tiny nummus coin gives me new respect for the humble follis of Anastatios being worth (M) forty of these nummi.
Here's the very precise dimensions of the Leo nummus. Weight: 1.11 g. As for diameter : 11 mm. The Decanummium of Theodoric the Great weighs 3.49 g.
I too have a Leo I nummus. This is larger and thicker than Anastasius, but I don't have the weight with me right now. It's 10mm, just 1mm larger than Anastasius. A denominated pentanummium(sp?) of Justin II is 5-nummi, and only 12mm. These little guys were quite small. I don't think there's 5 times as much metal in the 5-nummus than even the smallest 1-nummus.