Forgot to save some of my progress, the previous update note is now actually implemented.

Ok, I think I've narrowed down all the Diamond Mines. I wouldn't know because the sources I used didn't list all known Diamond Mines so I just checked each a bunch of countries. Anyway, Sierra Leone now has 1, Shengjing now has 1, Saskatchenwan now has 1, Bolivar now has 1, Liberia has the only active Deposit in this update, Guinea now has one, Windward Coast has the smallest possible Diamond Deposit (This is due to my understanding that they didn't have many Diamonds), Ghana now has one, Ubangi-Shari (Central African Republic) now has one.

I've rebalanced the Diamond mines a little, now there are less in Britain's market. Any Diamond Mine which has above a certain size will now spawn a single Diamond mine at game start. That means there is now one at game start in Arkansas in the USA, the NW Territories of Canada, Andhra in India, 1 in Botswana, 1 in East Angola, 1 in Zambezi, 2 in Nambia, 1 in China, 1 in Siberia, 1 in Brazil.