Ads
related to: crystal facts
Search results
Results From The WOW.Com Content Network
A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, ...
Selenite, satin spar, desert rose, and gypsum flower are crystal habit varieties of the mineral gypsum.. All varieties of gypsum, including selenite and alabaster, are composed of calcium sulfate dihydrate (meaning that it has two molecules of water), with the chemical formula CaSO 4 ·2H 2 O. Selenite contains no selenium, the similar names both derive from Greek selḗnē (σελήνη 'Moon').
Lead glass, commonly called crystal, is a variety of glass in which lead replaces the calcium content of a typical potash glass. [1] Lead glass contains typically 18–40% (by mass) lead(II) oxide (PbO), while modern lead crystal , historically also known as flint glass due to the original silica source, contains a minimum of 24% PbO. [ 2 ]
In crystallography, crystal structure is a description of ordered arrangement of atoms, ions, or molecules in a crystalline material. [1] Ordered structures occur from intrinsic nature of constituent particles to form symmetric patterns that repeat along the principal directions of three-dimensional space in matter.
Agate will form crystals within the reduced cavity, and the apex of each crystal may point towards the center of the cavity. The priming layer is often dark green, but can be modified by iron oxide resulting in a rust like appearance. [7] Agate is very durable and is often found detached from its host matrix, which may have eroded more quickly.
It was used as the crystal in crystal radio receivers, in which it was used as a point-contact diode capable of rectifying alternating current to detect the radio signals. The galena crystal was used with a sharp wire, known as a "cat's whisker", in contact with it. [28] In modern times, galena is primarily used to extract its constituent minerals.
The crystals are usually prismatic parallel to the c-crystal axis, and flattened perpendicular to the b-axis. Equant crystals are rarer. [ 2 ] [ 3 ] [ 5 ] They may also occur as stellate (star-shaped) groups, or encrustations with a bladed or fibrous structure. [ 5 ]
Group of precious and semiprecious stones—both uncut and faceted—including (clockwise from top left) diamond, uncut synthetic sapphire, ruby, uncut emerald, and amethyst crystal cluster. A gemstone (also called a fine gem , jewel , precious stone , semiprecious stone , or simply gem ) is a piece of mineral crystal which, when cut or ...