Isidore Kozminsky, The Magic and Science of Jewels and Stones
“ Pure specimens of alabaster were also employed as milk-stone talismans. Oriental alabaster, known as the Algerian onyx, is a solid crystalline carbonate of lime, precipitated from water in stalagmitic form. This Oriental alabaster is considerably harder than true alabaster which is easily scratched. Pliny writes of columns of alabaster over thirty feet in height. In ancient times it was regarded as a species of onyx, and was made into cups, vases and other utensils. Pliny says that it was “of the colour of honey, opaque and spirally spotted.” ”
