A silicate mineral, is a fibrous, naturally occurring material of varying chemical compositions. Asbestos is used in well over 3,000 products including building materials and goods. Asbestos fibers are flexible and resistant to heat, fire, chemicals, and electricity. This is why they have been used in home and business construction materials, automotive parts, and even textiles.
But when touched or injured, asbestos fibers rapidly break apart into minuscule fragments. They are easy to breathe in and too little to see. They can accumulate in your lungs and harm your health. The American government has outlawed all new applications for asbestos due to this. However, certain applications created before 1989 are still permitted.
Asbestos (/æsˈbɛstəs, æz-, -tɒs/ ass-BES-təs, az-, -toss) is a group of naturally occurring, toxic, carcinogenic and fibrous silicate minerals. There are six types, all of which are composed of long and thin fibrous crystals, each fibre (particulate with length substantially greater than width) being composed of many microscopic "fibrils" that can be released into the atmosphere by abrasion and other processes. Inhalation of asbestos fibres can lead to various dangerous lung conditions, including mesothelioma, asbestosis, and lung cancer. As a result of these health effects, asbestos is considered a serious health and safety hazard.
| Asbestos | |
|---|---|
 | |
| General | |
| Category | Silicate minerals |
| Strunz classification | 09.ED.15 |
| Dana classification | 71.01.02d.03 |
| Crystal system | Orthorhombic, monoclinic |
| Identification | |
| Formula mass | 277.11 g |
| Color | Green, red, yellow, white, gray, blue |
| Crystal habit | Amorphous, granular, massive |
| Cleavage | Prismatic |
| Fracture | Fibrous |
| Mohs scale hardness | 2.5.6.0 |
| Luster | Silky |
| Streak | White |
| Specific gravity | 2.4–3.3 |
| Optical properties | Biaxial |
| Refractive index | 1.53–1.72 |
| Birefringence | 0.008 |
| 2V angle | 20° to 60° |
| Dispersion | Relatively weak |
| Extinction | Parallel or oblique |
| Ultraviolet fluorescence | Non-fluorescent |
| Melting point | 400 to 1,040 °C (752 to 1,904 °F) |
Archaeological studies have found evidence of asbestos being used as far back as the Stone Age to strengthen ceramic pots, but large-scale mining began at the end of the 19th century when manufacturers and builders began using asbestos for its desirable physical properties. Asbestos is an excellent thermal and electrical insulator, and is highly fire resistant, so for much of the 20th century, it was very commonly used around the world as a building material (particularly for its fire-retardant properties), until its adverse effects on human health were more widely recognized and acknowledged in the 1970s. Many buildings constructed before the 1980s contain asbestos.
The use of asbestos for construction and fireproofing has been made illegal in many countries. Despite this, around 255,000 people are thought to die each year from diseases related to asbestos exposure. In part, this is because many older buildings still contain asbestos; in addition, the consequences of exposure can take decades to arise. The latency period (from exposure until the diagnosis of negative health effects) is typically 20 years. The most common diseases associated with chronic asbestos exposure are asbestosis (scarring of the lungs due to asbestos inhalation) and mesothelioma (a type of cancer).
Many developing countries still support the use of asbestos as a building material, and mining of asbestos is ongoing, with the top producer, Russia, having an estimated production of 790,000 tonnes in 2020.
English
Alternative forms
- asbestus (dated)
Etymology
From Old French abestos, from Latin asbestos, itself from Ancient Greek ἄσβεστος (ásbestos, “unquenchable, inextinguishable”), from ᾰ̓- (a-, “not”) + σβέννῡμῐ (sbénnūmi, “I quench, quell”).
Pronunciation
- (Received Pronunciation) IPA(key): /æsˈbɛs.tɒs/, /æsˈbɛs.təs/, /æzˈbɛs.təs/
