Etherium shards are a type of currency that can be traded for lobbyist tokens at the Etherium Forge. It costs one to make a Clout Tier 2 silver token, two for a CT3 gold token, and four for a CT4 platinum token. Currently, platinum tokens are the only source of CT4 gear asides from dark god tokens, which are also made with etherium shards.
Etherium Shards can be found randomly while wandering around Quite Hill, ME. There is a 2% chance of getting a random event that will give you one for picking the first option. You can also use Kongregate kreds to buy shards if you are so inclined.