Somewhere between R9 - R11 or 12 is fine, inscribable, max etc. etc.
Greens of the same skin (links below) are fine as well.
http://wiki.guildwars.com/wiki/Stone_Crusher_(weapon)
http://wiki.guildwars.com/wiki/Kanaxai%27s_Mallet
http://wiki.guildwars.com/wiki/Maul_of_the_Hierophant
WTB Stone Crusher
Yoshikuni Mahsu