Gems are one of the 31 Rare Resources in the game and available from the beginning. They appear as a small patch of blue, red, and green sparkling gems and can be found on the sides of mountains, rather than on flat land. Like with all rare resources on land, they can be gathered by sending a Merchant from the Market to the resource location. Gems provide the following benefits:Classical Age. The Greeks may gather Knowledge from the beginning, making an early exploitation of this resource more useful. The border expanding effect isn't all that significant, when compared to other methods of border expansion (e.g., Civic Research adds +4 each time), but it might still prove useful.