Geosciences
Compare and contrast the four basic igneous compositions: basaltic (mafic), granitic (felsic), andesitic (intermediate), and ultramafic. Igneous rocks are composed mainly of silicate minerals. Chemical analyses show that silicon and … Read More
Most minerals you see while walking around an outcrop or a road cut reflect the local geology. The Sierra Nevada in California, which is primarily granitic, has an abundance of … Read More
The word mineral comes from the Latin minera, or mine. Until the nineteenth century, minerals were simply things that came out of mines—things that had economic value, like gold, various … Read More
A shear zone is a very important structural discontinuity surface in the Earth’s crust and upper mantle. It forms as a response to inhomogeneous deformation partitioning strain into planar or … Read More
Topaz is a silicate mineral of aluminium and fluorine with the chemical formula Al2SiO4(F,OH)2. Topaz crystallizes in the orthorhombic system, and its crystals are mostly prismatic terminated by pyramidal and … Read More
Identify and describe the six major igneous textures. The term texture is used to describe the overall appearance of a rock based on the size, shape, and arrangement of its … Read More
Distinguish between compositional and structural variations in minerals and provide one example of each. Many people associate the word crystal with delicate wine goblets or glassy objects with smooth sides … Read More
How easily minerals break or deform under stress is determined by the type and strength of the chemical bonds that hold the crystals together. Mineralogists use terms including hardness, cleavage, … Read More
