sillimanite

American  

[sil-uh-muh-nahyt] / ˈsɪl ə məˌnaɪt /

noun

1. a mineral, aluminum silicate, Al 2 SiO 5 , occurring in the form of long, slender, and often fibrous crystals.

---

sillimanite British  

/ ˈsɪlɪməˌnaɪt /

noun

1. a white, brown, or green fibrous mineral that consists of aluminium silicate in orthorhombic crystalline form and occurs in metamorphic rocks. Formula: Al 2 SiO 5

---

sillimanite Scientific  

/ sĭl′ə-mə-nīt′ /

1. A usually white, pale-green or brown orthorhombic mineral occurring as long, slender, fibrous crystals in metamorphic rocks. It is a polymorph of andalusite and kyanite, but can form at higher temperatures than either of these. Chemical formula: Al ₂ SiO ₅ .

---

Etymology

Origin of sillimanite

1825–30; named after B. Silliman; see -ite ¹

Example Sentences

Quartz is a good example as slightly different forms are stable between 0°C and 1800°C. The minerals kyanite, andalusite, and sillimanite are polymorphs with the composition Al2SiO5.

From Textbooks • Jan. 1, 2015

Rearrange the following minerals in order of increasing metamorphic grade: biotite, garnet, sillimanite, chlorite.

From Textbooks • Jan. 1, 2015

The rocks of the sillimanite zone were likely heated to over 700°C, and therefore must have buried to depths between 20 km and 25 km.

From Textbooks • Jan. 1, 2015

At a high temperature, about 1350� C., it becomes transformed into sillimanite, changing in specific gravity from 3.6 to 3.2.

From Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 8 "Cube" to "Daguerre, Louis" by Various

There is also a long list of accessory minerals which are present in gneisses with more or less frequency, but not invariably, as garnet, sillimanite, cordierite, graphite and graphitoid, epidote, calcite, orthite, tourmaline and andalusite.

From Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 2 "Gloss" to "Gordon, Charles George" by Various