Featured Iron Scale Weight; Dual, Lead Seal, 500G: Odd Symbol

It's ~1 5/8" diameter, ~1 13/16" high to the shoulder.The 'seal', which is unmarked, may just be a plug; it doesn't rattle like it would if it had a shot fill. The markings suggest it was designed for use as a direct 500G, or as a 10X (5KG) through some multiplier linkage. Its actual weight is 500.4 grams; if used for trade at 10 pounds, it would give an extra ~1 pound, as 5KG is 11.023 pounds.
My question has to do with the symbol indicating pounds; I've never seen that mark, an' wonder when an' where it was in common use, which may indicate the age of this chunk of iron. Thanks for lookin'!

 

It occurs to me that perhaps at one time an (English?) pound was equal to 500G...as in, among other possibilities, Pound Sterling?

 

That seal is in fact a formed plug; a closed end cylinder ~0.200" deep with an ~1/8" flange that has about 120 degrees of its circumference missing. I'm loath to monkey with it, much as I'd like to see what may lie beneath.

 

What was the actual weight of the 'pound' in Pound Sterling? I believe silver, in Troy measure, is 12 Troy ounces, not 16, as in Avoirdupois.

 

Yes, I have examples of the plug type, with marks. I understand the concept. First, the weight is only 0.4 Grams off...an' over, at that. What would be the purpose of tampering so obviously, an' in that direction, Davey?

 

So there is not/was not any equivalency between the currency, whether coin or banknote, an' an actual pound of sterling by whatever weight?

 

That is actually metric and still used, 1 pond or Pfund equals 500 grams, half a kilo.

The term Pound Sterling comes from the Medieval Dutch "pond oosterling", pound easterner, meaning a German pound. Until the Austrian Maria Theresia coins, German silver coins were more reliable than any other coin in Europe, so a silver pond oosterling was the best pond/pound.
The Dutch and Frisians traded with Britain and paid with the reliable pond oosterling. The Brits thought the double o was a double 0, and deleted what they thought were zeros, and the term pound sterling was born.
Nowadays it is written with capitals, Pound Sterling, even though the S was not the first letter when first introduced.

 

WOW! There is a whole lot to like in both of your comments...Thanks! I am very much enlightened an' far better informed, an' most grateful for it all!