Exhibited and illustrated: Field of Stones, New York: China 2000 Fine Art, 2001, and published in the exhibition catalogue, plate 17.
Marble is a non-foliated metamorphic rock resulting from the metamorphism of limestone, composed mostly of calcite (a crystalline form of calcium carbonate, CaCO3). This metamorphic process causes a complete re-crystallization of the original rock into an interlocking mosaic of calcite, aragonite and/or dolomite crystals. The temperatures and pressures necessary to form marble usually destroy any fossils and sedimentary textures present in the original rock. Pure white marble is the result of metamorphism of very pure limestone. The characteristic swirls and veins of many colored marble varieties are usually due to various mineral impurities such as clay, silt, sand, iron oxides, or chert which were originally present as grains or layers in the limestone. Yellow coloration is often due to the presence of iron oxides. The yellow marbles in China are mainly found in Xichuan, Henan province and Baohing, Sichuan province. Those from Henan are called Song Xiang Huang; those from Sichuan are called Huang Xian Yu.