Apple's Human Interface Guidelines (HIG) suggest all app icons be a rounded square. This results in the current launcher icon being very out of place next to built-in and other 3rd party applications (see screenshot).
For an icon that would fit the OS better, I suggest the present grass block at an angle on a stone background. Another option may be a grass background with a tool from in-game, similar to the Xcode or Text Edit icon.
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