A white alabaster bust, Italian school signed with I. Jackson, Roma, Italy in 1857.
Alabaster is a type of rock or mineral and often used for carving. The word Alabaster is differently used by archeologists and geologists. The word Alabaster includes varieties of two different minerals: a fine-grained massive type of gypsum and a fine-grained banded type of calcite. Geologists define alabaster only as the gypsum type.
Both types of alabaster have been used throughout history primarily for carving decorative art and have similar properties. Both are lightly colored, translucent, and are relatively soft. The two kinds of minerals can be distinguished by their different hardness. The gypsum type of alabaster is so soft that a fingernail can scratch it, while calcite cannot be scratched with a fingernail.