Answer:
Flat as a leaf, round as a ring. Has two eyes, can't see a thing.
A certain wizard resided in a city made from this gemstone.
I wear a red robe, with staff in hand, and a stone in my throat.
Crooked as a rainbow, and slick as a plate, Ten thousand horses can't pull it straight.
What word has kst in the middle, in the beginning, and at the end?
People take me on walks and I run and have fun. What am I?