The Rock Quarry is unlocked at level 1 and can be purchased from Shop > Production tab. THERE ARE NO BUILD STAGES FOR ROCK QUARRY.
Stones are also obtainable by clicking stone deposits on our own frontiers, however this will use a lot of your energy. It will be very wise to construct the Rock Quarry as soon as you can so that you have another option to get stones.
* There are goals which require you to gather stones from your frontier - always leave a few piles of stone deposits around on your frontier for the use of these goals. We can not purchase additional stone deposits to place on our frontiers, so once they are gone, they are gone.