Serpentine rock is used as an ornamental stone for interior decoration, because it takes a high polish and has pleasing colors, various shades of green. It is however decidedly soft and will stand very little exposure to weather, and it is also filled with seams which make it difficult to get out large slabs. Serpentine rock occurs fairly commonly in the metamorphic belt of New England and the Piedmont Plateau, and in some of the western states, especially California, Oregon, and Washington. Ophiolite _Ophicalcite_ This name is given to marbles which are streaked and spotted with serpentine. They are a mixture of green serpentine and a white or nearly white calcite, magnesite or dolomite in variable proportions. Ophicalcite occurs in and with metamorphic rocks, and represents an impure limestone which has been metamorphised, the lime becoming marble, and the impurities becoming such silicates as pyroxene, amphibole, or olivine. This metamorphic rock has then come into the zone of ground-water and the silicate minerals have been changed by hydration to serpentine. Ophicalcite is then a metamorphic rock, in which secondary chemical changes have since taken place. It may have a wide range of accessory minerals present, such as magnetite, chromite, pyrope among the garnets, olivine, etc. Verde antique is a trade name for one of the ophiolites. While not abundant, ophicalcite is in good demand as an ornamental stone for interior work; for it takes a high polish, and is beautiful; but, on the other hand, it will not stand exposure to the weather for the calcite is soluble, and there are numerous seams and cracks in it making it difficult to obtain large slabs. It occurs in Quebec, Canada, in the Green Mountains of Vermont, and in the Adirondack Mountains. CHAPTER V MISCELLANEOUS ROCKS There are a few rocks which do not fit into any of the three groups described, such as concretions, geodes, meteorites, etc., and they are gathered together here. There is also one type of rock, which really belongs among the minerals, but is likely not to be so recognized at first glance, and that is the material filling veins. These last are sometimes designated “vein rocks,” but are really massive deposits of one, two or more minerals, and should be referred to the minerals when found. Concretions