There is no way to get a claim back once the tile has been used. This is a design decision: you are forced to think ahead how to use a limited resource.
There is one exception that I am aware of: if one bulldoze the tile before it is built, the claim is returned. So miss-clicks can be corrected if you immediately realize it or if the game is on pause.
Update: As mentioned by DMA57361 in a comment, if another player beats you to the tile, your claim is refunded as well.
Based on my testing the output is the same for the glass kiln and other buildings you place over input resources. Doing so is advisable when you do not need to harvest the resource directly (it's not a rarity to leverage) and to prevent other factions from reaching these resources.
Best Answer
A Neutral Colony has the following effects:
-The colony adds artificial market pressures to the game mostly in power, food, water, oxygen and fuel.
-The larger the colony the more a pleasure dome will produce.
-If the colony dies from overpriced something all players lose the game
There is an ongoing discussion going on here on Reddit about the characteristics and effects of a Neutral Economy.