It's not really for the OP, but for anybody poking through the forums later, looking for an answer.
Money in D&D can be really confusing. I played using both D&D(1e) and AD&D(1e) materials and they had different currency systems. Early D&D(1e) didn't set the value of electrum pieces and got...
D&D (4e) Currency
10 cp = 1 sp
100 cp = 10 sp = 1 gp
10,000 cp = 1,000 sp = 100 gp = 1 pp
Electrum pieces (still worth 5sp each) were dropped to simplify the game currency by making it completely decimal.
The next two were borrowed from the Neverwinter Nights videogame series.
Astral Diamond...