Silica sand, the most important material entering glass is acidic character. Silica is the most common substance in the earth crust. It is estimated that 80% of earth crust is silica, calculated to a depth of 10 miles below sea level, in the form of quartz, it is a major constituent of all rocks. Granites is a mixture of quartz, feldspar and mica.
Sand is a product chemical and mechanical disintegration of rocks under the influence of weathering and abrasion. The predominating material is quartz. When the sand is comparatively recent in origin, the particles are angular and sharp pointed. Older sand has smooth rounded grains. Transportation of sand by water, its settling in river deltas such as that dredged in Beta Glass and along the shorelines of the ocean can be observed today and gives a picture of what happened millions of years ago.
The effect of the action of waves, tides and shore currents have tended to separate the heavier quartz particles from accompanying feldsparthic material. The wind has also been an important factor in sorting the particle washed on the sea shore.
On the shores of the ancient sea where deposited some of the sand quarried at the present time for glass making, lands bearing the sand deposit slowly subsided and was subsequently raised hundreds of feet above sea level and subjected to enormous pressure during the formation. The action of heat, pressure and percolating water tend to consolidate the sandstones, the clay into limestone, the residue of plants into coal.
Erosion by water and wind has chiseled valleys and has in some cases brought the sandstone to the surface again. The rate of disintegration depends largely upon bond connecting the quartz, it will lessen more rapidly than when silica clay is appreciably soluble in water containing carbon dioxide.
When a stream enters a lake the current is checked and the load of sand and mud gradually settles to the bottom. Downstream in the open valley, sand and mud are spread over the alluvial flat during floods, while the main stream continues by way of estuary or delta, to sweep the bulk of the material into the sea.
Glass is also a typical amorphous substance which is mostly silicates that have had insufficient time to arrange themselves into the regular patterns of crystals, either because of rapid cooling from the molten state or because the original melt was extremely viscous from the start.
The four positive charges of Si4+ are balanced by four negative oxygen ions, O2-, thus leaving each tetrahedron with four charges. By themselves these tetrahedral building unit would fly apart in consequence of resulting electrical repulsion. To build them together as in crystals, they must be cemented or linked so that the charges are neutralized. The linkages result in building up of structures such as separate pairs and rings, single and double chains.
