A coarse-grained [sand], blast sand, is used with compressed air to clean the walls of brick and stone buildings and to carve designs on monument stones, such as marbles. Some coarse sand is also used as a filtering sand in purifying water. These types of sand have been produced from the [Gulf Coastal Plain] as well as from other areas of Texas.
[Sand] grains, when nature cements them together, make up the [sedimentary] rock [sandstone]. Some sandstones form when underground water carrying dissolved mineral matter moves through loose sand. As the dissolved mineral matter comes out of solution, it forms a cement that binds the sand grains together.
The cement may be material such as [calcite] (calcium carbonate), [quartz], [chalcedony], or [opal], which are silica minerals, and [limonite] and [hematite], which are iron oxides. [Clay] also may serve as a cement. It is either deposited along with the [sand] or is formed from weathered [feldspar] sand grains.
The color of the cementing material helps determine the color of the rock. Iron oxide cement, for example, causes the [sandstone] to have a reddish, yellowish, or brownish color. Sandstones also are white, black, gray, green, or cream colored.
Ordinarily, sandstones break through the cementing material, not through the [sand] grains. Thus, the broken surface of the rock feels rough and gritty. Some [quartz] sand grains, however, are tightly cemented with silica to form an extremely hard and compact rock. If this rock breaks smoothly through the grains instead of between them, it is known as [quartzite]. Some of this [sedimentary quartzite] occurs in the Texas [Gulf Coastal Plain] in the [Tertiary] Catahoula strata. (Another kind of quartzite is described on pp. [84]-85.)
[Sandstone] from the [Eocene] Wilcox Group of strata of northwestern Zavala County, Texas.
Ordinary sandstones are seen at the surface in many localities in Texas, and a number of them have been used as building stones. Some of the places where sandstones occur are in the [Cambrian] and [Pennsylvanian] [formations] of the [Llano uplift] area of central Texas and in the Pennsylvanian, [Permian], and Lower [Cretaceous] formations of north-central Texas. [Tertiary] sandstones occur in the Texas [Gulf Coastal Plain], and Triassic sandstones are found along the edges of the Texas [High Plains]. [Sandstone] is also found in many formations of the Trans-Pecos country of west Texas.
Sandstone. See [Sand and Sandstone].
Satin Spar. See [Gypsum].