Boraxo Pit #1
- Catalog Number:
- 41163
- Specimen Count:
- 1
- Precise Locality:
- Locality:
- US Pacific (CA, OR, WA)
- Collecting Locality:
- North America, United States, California, Inyo County
- Cabinet:
- 07
- Drawer/Shelf:
- 06
Despite the abundance of silicons in the Earth's crust, not all minerals contain silicon. The atoms of many metals, which tend to lose electrons and become positively charged, like to bond with other atoms or groups of atoms that tend to gain atoms and become negatively charged. For example, atoms of sodium, a metal, and chlorine, a non-metal, pair up in equal numbers to form sodium chloride, also known as halite (or common table salt). Other important types of non-silicate minerals include carbonates, with metals bonded to groups of carbon and oxygen atoms; oxides, with metals joined to oxygen alone; sulfides, which consist of metal and sulfur atoms; and sulfates, in which groups of sulfur and oxygen atoms are joined with metal atoms.
Since antiquity, humans have made pottery from clay, which consists of fine particles of silicate minerals. Kaolinite is an aluminum silicate mineral, and it is the main component of porcelain, a particularly hard type of ceramic. Clay, which is used to make other types of pottery, may contain silica and grains from sedimentary rocks. Quartz, also referred to as silica or silicon dioxide, is a key component of another important solid material: glass. In the ancient Middle East, humans made glass by heating silica with alkali that was made from the ashes of plants. Other minerals such as calcium, lead, calcium, and manganese were added to improve the glass. Metals and metallic oxides were also added to color the glass or to make it clear, since natural glass tends to be slightly colored from impurities in the sand. Ruby red is made from powdered gold, while an orangey-red is produced by copper oxides. If the glass with copper oxide is heated too much, it will turn green. Cobalt and iron can make blue glass, and manganese is used for purple. Antimony or manganese oxide will produce clear glass. Glass for specialized purposes, like cookware and optical instruments, may require additives, such as boron oxide or lead oxide.