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Jasper breaks with a smooth surface and is used for ornamentation or as a gemstone. It can be highly polished and is used for items such as vases, seals, and snuff boxes. The density of jasper is typically 2.5 to 2.9 g/cm 3. [4] Jaspillite is a banded-iron-formation rock that often has distinctive bands of jasper.
Minerals often have a highly distinctive fracture, making it a principal feature used in their identification. Fracture differs from cleavage in that the latter involves clean splitting along the cleavage planes of the mineral's crystal structure, as opposed to more general breakage. All minerals exhibit fracture, but when very strong cleavage ...
A rough specimen of bloodstone. Heliotropes (from Ancient Greek ἥλιος (hḗlios) 'sun' and τρέπειν (trépein) 'to turn') (also called ematille, Indian bloodstones, or simply bloodstones) are aggregate minerals, and cryptocrystalline mixture of quartz that occurs mostly as jasper or sometimes as chalcedony (translucent).
fracture of the distal third of the humerus resulting in entrapment of the radial nerve: Holstein-Lewis fracture at Orthopedic Weblinks Holdsworth fracture: Sir Frank Wild Holdsworth: unstable spinal fracture-dislocation at the thoracolumbar junction: Thoracic Spine Fractures and Dislocations at eMedicine: Hume fracture: A.C. Hume
A conchoidal fracture is a break or fracture of a brittle material that does not follow any natural planes of separation. Mindat.org defines conchoidal fracture as follows: "a fracture with smooth, curved surfaces, typically slightly concave, showing concentric undulations resembling the lines of growth of a shell". [ 1 ]
This is a list of gemstones, organized by species and types. Minerals There ... Jasper; Petrified wood; Sard; Citrine (var.) Druzy (var.) Flint (var.) Herkimer ...
(However, the term prase is also used to describe chlorite-included quartz, and to a certain extent is a color-descriptor, rather than a rigorously defined mineral variety.) Chrysoprase is cryptocrystalline, which means that it is composed of crystals so fine that they cannot be seen as distinct particles under normal magnification.
fracture front – the line separating the rock that has been fractured from the rock that has not; fracture tip – the point at which the fracture trace terminates on the surface; fracture trace – the line representing the intersection of the fracture plane with the surface; Griffith cracks – preexisting microfractures and flaws in the rock