The Witches coven are making a potion and Ethel, Glinda, Locasta and Circe each add a different ingredient. When the potion is finished, there is 1/4 of the bat blood left, 1/3 of the knotgrass, 1/2 of the moonstone and 5/8 of the unicorn hair. Ethel used the most. Glinda used the least. Locasta used more than Circe. Who used the moonstone?