"Sandstones are composed of rounded and angular grains of sand so cemented and compacted together as to form a solid rock. The cementing material may be either silica, carbonate of lime, an iron oxide or clayey matter."
They include some of the most beautiful and durable stones for exterior construction, and on account of the ease with which they can be worked and their wide distribution throughout the country, are more extensively used for exteriors than any other stone.
The grains of sand themselves are nearly the same in all sandstones, being generally pure quartz, the character of the stone depending principally upon the cementing material. If the cementing material is composed entirely of silica, the rock is light colored and generally very hard and difficult to work. When the grains have been cemented together by fusion or by the deposition of silica between the granules, and the whole hardened under pressure, it is almost the same as pure quartz and is called quartzite - one of the strongest and most durable of rocks. "If the cementing material is composed largely of iron oxides the stone is red or brownish in color and usually not too hard to work readily. When the cementing material is carbonate of lime the stone is light colored or gray, soft and easy to work." Such stones do not as a rule weather well, as the cementing material becomes dissolved by the rain, thereby loosening the grains and allowing the stone to disintegrate. Clay is still more objectionable than lime as a cementing material, as it readily absorbs water and renders the stone liable to injury by frost.
In some sandstones part of the grains consist of feldspar and mica, which have a tendency to weaken the stone.
Sandstones are of a great variety of colors; brown, red, pink, gray, buff, drab or blue, in varying shades, being common varieties; the color being due largely to the iron contained in the stone. The oxides of iron do no harm in the stone, but no light-colored sandstone should be used for exterior work which contains iron pyrites (or sulphate of iron), as the iron is almost sure to stain or rust the stone.
Sandstones vary in texture from almost impalpable fine-grained stones to those in which the grains are like coarse sand. All other conditions being the same, the fine-grained stones will be the strongest and most durable and take the sharpest edge. Sandstones being of a sedimentary formation, they are often laminated, or in layers, and if the stone is set "on edge," or with its natural bed or surface parallel to the face of the wall, the surface of the stone is quite sure in time to disintegrate or peel off. All laminated stones should always be laid on their natural bed. When freshly quarried, sandstones generally contain a considerable quantity of water, which makes them soft and easy to work, but at the same time very liable to injury by freezing if quarried in winter weather. Many Northern quarries cannot be worked in winter on this account. Most, if not all, sandstones harden as the quarry water evaporates, so that many stones which are very soft when first quarried become hard and durable when placed in the building. Such stones, however, should not be subjected to-much weight until they have dried out.
There is a great abundance of fine sandstone of all colors distributed throughout the United States, so that it is not difficult to get a first-class stone for any building of importance. Most of the sandstones in the Eastern part of the country are either red or brown in color there being no merchantable light sandstones east of Ohio.
159. The following are the best known sandstones in this country, any of which are good building stones:
Connecticut brownstone includes all the dark brown sandstones quarried in the neighborhood of Portland, Conn. It is a handsome dark brown stone, tinted slightly reddish, has a fine even rift, is easy to work, and gives a beautiful surface when rubbed. This stone is decidedly laminated, and the surface will soon peel if the stone is set on edge. When laid on its natural bed, however, it is very durable. This was the first sandstone quarried in the country, and great quantities of it have been used in New York City.
Longmeadow Stone. - This is a reddish-brown sandstone quarried principally at East Longmeadow, Mass. It is an excellent building stone, without any apparent bed, and may be cut any way. It varies from quite soft to very hard and strong stone, and should be selected for good work. It has been largely used throughout the New England States for the past fifteen years.
Potsdam Red Sandstone, from Potsdam, N. Y., is a quartzite and one of the best building stones in the country, being extremely durable and equal to granite in strength. It was used in the buildings of Columbia College, New York City; All Saints Cathedral, in Albany, and in the Dominion Houses of Parliament, in Ottawa, Canada. There are three shades, chocolate, brick-red and reddish-cream.
Hummelstown Brownstone, from Hummelstown, Pa., is a medium fine-grained stone, bluish-brown or slightly purple in color, the upper layers being more of a reddish-brown and much resembling the Connecticut stone. The stone compares very favorably with the other brownstones mentioned, and is in very general use in the principal Eastern cities.
North Carolina, West Virginia and Indiana contain quarries of brownstone which supply the local demand and which are worthy of a wider distribution, particularly that of North Carolina.
Fond du Lac, Minnesota, furnishes a reddish-brown sandstone closely resembling the Connecticut brownstone, but much harder and firmer. "The stone consists almost wholly of quartz cemented with silica and iron oxides."
Ohio Stone. - The finest quality of light sandstone in the United States is quarried in the towns of Amherst, Berea, East Cleveland, Illyria and Independence, Ohio, and is commonly known as Ohio stone or Berea stone. It is a fine-grained, homogenous sandstone, of a very light buff, gray or blue-gray color, and very evenly bedded. The stone is about 95 per cent, silica, the balance being made up of small amounts of lime, magnesia, iron oxides, alumina and alkalies. There is but little cementing material, the various particles being held together mainly by cohesion induced by the pressure to which they were subjected at the time of their consolidation. They are very soft and work readily in every direction, and are especially fitted for carving.
"Unfortunately the Berea stone nearly always contains more or less iron pyrites and needs to be selected with care. Most of the quarries, however, have been traversed by atmospheric waters to such a degree that all processes of oxidation which are possible have been very nearly completed." *
The stone can be furnished in blocks of any desired size and of uniform color. The stone is shipped to all parts of the country, and is in great demand for fine buildings. Mr. H. H. Richardson, the celebrated architect, often used it in contrast with the Longmeadow sandstone for trimmings and decorative effects. The stone contains from about 6 to 8 per cent, of water when first taken from the quarry, and about 4 per cent, when dry. The stone cannot be quarried in winter on account of the splitting of the stone caused by the freezing of the water contained in it. There are some fourteen or fifteen different companies that quarry this stone for the market.
"The Waverly sandstone comes from Southern Ohio. This is a fine-grained, homogenous stone of a light drab or dove color, works with facility, and is very handsome and durable. It forms the material of which many of the finest buildings in Cincinnati are constructed, and is, justly, highly esteemed there and elsewhere."†
Ohio is the largest producer of sandstone of any State in the Union.
At Warrensburg, Mo., is quarried a gray sandstone which has been used in many important buildings in Kansas City.
* " Stones for Building and Decoration," pp. 276-277. † Baker, " Masonry Construction," p. 30.
The Rocky Mountain region also furnishes great quantities of fine sandstones. In Arizona is quarried a very fine-grained chocolate sandstone, which takes a fine edge and is excellently adapted for rubbed and moulded work. A considerable quantity of it is used in Denver, Col., on account of its pleasing color, and it is also shipped east of the Missouri River.
At Manitou, Col., are inexhaustible quarries of a fine red stone, much resembling the Longmeadow stone of Massachusetts, but of a lighter red color. It has no apparent bed and weathers well. It has sufficient strength for ordinary purposes. At Fort Collins. Col., is quarried a much harder and slightly darker stone, which is an excellent stone for almost any purpose. It has sufficient strength for piers and columns, and is hard enough for steps and thresholds. It is much harder to cut than the Manitou stone, and hence is more expensive, but it is more durable. This stone has been shipped as far East as New York City. Colorado also contains an inexhaustible supply of sandstone flagging, admirably adapted for foundations and sidewalks; it is as strong as granite, and may be quarried in slabs of almost any size or thickness.
A red and buff sandstone is quarried at Glenrock, Wyoming, which has been used in Omaha, Nebraska.
California has fifteen quarries of sandstone, the larger number of which are in Santa Clara County. Stanford University is built of a light-colored sandstone quarried at San Jose, Cal.
Owing to the sparsely settled condition of the country and the lack of railroad facilities, the building stones of the Western portion of the United States have been but little developed, but with the building up of the country the quarrying industry will undoubtedly become one of great importance.