While randomly exploring the internet, I found that the ancient Slavs were using bars of 200g of silver called Grivna, used both as weight standard, and currency. I thought you would love it!

what's also cool is that they had a fixed conversion between silver and furs...

1 grivna of silver (204 g) = 4 grivnas of kuna (51 g) = 80 nogata coins = 100 kunas (marten furs) = 200 rezans = 400–600 vekshas (squirrel furs)