On Petpet Park where can i find the gems for grandmas necklace

First, head over to the Knights Keep area on the map. Once your there, you'll see a sign next to Sir Liams Castle Defender game that says "Wailing Tunnels", go down there and there will be signs hinting you to where the gems are. Oh, but before any of this, go to the "Petpet Emporium" in the Market Lane area on the map and buy a mining pick for 75 park points. Once you've done that, head back down the "The Wailing Tunnels" to start your quest.