Rock Runeys are one of the four types of Runeys in Rune Factory Frontier. They are purple in color and resemble rocks. They eat Tree Runeys and prefer to like near buildings, so they prosper the best around the Business District. Rock runeys can easily decrease in number as they don't multiply in great numbers and Water Runeys easily eat them.
If you're running out of Rock runeys, the best thing to do is to take an area and empty out the runeys there, preferably the Business District or the Public Square. There, place a lot of water runeys and several Grass runeys. Once the Grass runeys and Water runeys are about the same in number, place in a couple of Tree runeys. Those Tree Runeys will soon multiply. Once you have about 20 Tree runeys in the area, place a couple of Rock runeys there. The water runeys should be completely gone by now, and if they aren't take them out with your Harvester. Simply wait for a few days in the game, and you'll soon have an area filled with rock runeys.
Remember to add a few Tree Runeys every now and then since the Tree Runeys will decrease in number. You can take out as much Rock runeys as you want and spread them over to other areas as thy have multiplied.
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