Ads
related to: anhedral crystals geology
Search results
Results From The WOW.Com Content Network
Euhedral pyrite crystals A subhedral sample showing sharp to anhedral pyrargyrite crystals. Euhedral and anhedral are terms used to describe opposite properties in the formation of crystals. Euhedral (also known as idiomorphic or automorphic) crystals are those that are well-formed, with sharp, easily recognised faces.
Anhedral crystals do not, usually because the crystal is one grain in a polycrystalline solid. The flat faces (also called facets ) of a euhedral crystal are oriented in a specific way relative to the underlying atomic arrangement of the crystal : they are planes of relatively low Miller index . [ 10 ]
In mineralogy, crystal habit is the characteristic external shape of an individual crystal or aggregate of crystals. The habit of a crystal is dependent on its crystallographic form and growth conditions, which generally creates irregularities due to limited space in the crystallizing medium (commonly in rocks ).
The biotite crystals are 1–3 mm across, being more or less euhedral; but they contain small inclusions of titanite and magnetite, indicating that biotite crystallization began after them. The distinguishing feature of the Kuna Crest granodiorite is the presence of anhedral crystals of hornblende abounding in inclusions of the other minerals.
The crystals can occur either individually, as interconnected, form groups on plates or even in druzy form. Crystal masses can also form veins sometimes. [2] Individual crystals are euhedral, meaning they have well defined faces. When on a matrix, the mineral takes a granular habit, meaning the crystals become anhedral. [5]
In geology, texture or rock microstructure [1] refers to the relationship between the materials of which a rock is composed. [2] The broadest textural classes are crystalline (in which the components are intergrown and interlocking crystals), fragmental (in which there is an accumulation of fragments by some physical process), aphanitic (in which crystals are not visible to the unaided eye ...
Pyrrhotite, and other opaque minerals can be identified optically using a reflected light ore microscope. [19] The following optical properties [20] are representative of polished/puck sections using ore microscopy: Photomicrograph of pyrrhotite under reflected light appearing as cream-pink to beige irregular anhedral masses (5x/0.12 POL).
Microcline may be chemically the same as monoclinic orthoclase, but because it belongs to the triclinic crystal system, the prism angle is slightly less than right angles; hence the name "microcline" from the Greek "small slope". It is a fully ordered triclinic modification of potassium feldspar and is dimorphous with orthoclase. Microcline is ...