Crystalline

[Lat. crystal lin us.] Consisting of, or resembling, crystal; as, crystalline gla . -Bright; clear; diaphanous; pellucid; transparent; as, "the crystalline sky." - Milton. C. lens, or C. humor. (Anat.) The lens of the eye, a lentiform pellucid substance, enclosed in a membranous capsule, and situated in a depre ion in the anterior part of the vitreous humor. See EYE. C. rocks. (Geol.) The name given to such rocks as granite, quartzite, marble, and others, which show by their crystalline structure that they have been brought into their present state owing to the action of chemical forces. In the early history of geology, such rocks are called primitive , but they are certainly not limited to any geological age, examples being found in the newest as well as the oldest. Even granite is comparatively modern, and there is no reason why crystalline rocks should not be at the present time in course of formation. Crystallizable, a . That may be crystallized. Crystallization, n. (Chem.) The spontaneous a umption of well-defined geometrical forms by bodies in pa ing from the fluid, or aëriform, state to the solid condition. Bodies not capable of a uming the crystalline form are termed amorphous or colloid ; those which form crystals, crystalloid. When a substance crystallizes in two distinct forms, which cannot be derived from the same original, it is said to be dimorphous . Sulphur, for instance, will crystallize in octohedra or prismatic crystals. Some substances are even trimorphous . Sulphate of nickel crystallizes in right rhombic prisms, square-based octohedra, and oblique rhombic prisms, according to the temperature at the time of evaporation. Bodies crystallizing in similar forms are called isomorphic. The alums and fluor-spar; carbon, gold, copper, and their compounds; the pota ium compounds of chlorine, iodine, bromine, and fluorine, form isomorphous groups. C. may be effected in several ways-by evaporation, by sublimation, by fusion, or by slow electrical action. It sometimes happens that precipitates are thrown down in a crystalline form; thus, when tartaric acid is added to a solution of potash, the tartrate of potash falls down in minute crystals. C. by evaporation is effected either by allowing a hot saturated solution of the salt to cool gradually, or by spontaneous evaporation. In the former case the ma es of crystals are small and confused. Where single perfect crystals are required, the method of crystal-feeding invented by Leblanc must be resorted to. A small but perfect crystal is first obtained by one of the methods mentioned, and placed in a cold concentrated, but not saturated, solution of the substance in question, after which the cгувtal is turned regularly twice every day, taking care to expose a fresh surface each time, until the crystal has reached the desired size. As the solution becomes weaker, it should be replaced by a fresh quantity of the original strength. Great care must be taken not to use a saturated solution, otherwise fresh crystals will form in the ve el, and on the original crystal. A gla plate may be used to lay the crystal on in the solution, and a pair of horn or boxwood tweezers are better than the fingers for turning it. By these means crystals of very large size may be made. The solution should, as much as po ible, be kept at the same temperature, and the crystal should be turned very regularly. C. by fusion is resorted to in the case of metals and other insoluble substances. The metal, or other body, is melted in a ladle or crucible, and allowed to cool until the top-crust is solid; it is then pierced with an iron rod, and the melted substance not yet solidified is allowed to run out. Fine ma es of crys tals of bismuth and sulphur may be obtained in this way. Many salts do not appear to be capable of crystallizing without holding a certain portion of water in combination, termed water of crystallization. Thus, ordinary carbonate of soda has ten equivalents of water united with it. Some crystals part with this water very easily, losing their crystalline form, and falling to powder merely by exposure to the atmosphere. Such salts are called efflorescent , in contradistinction to those which absorb water from the atmosphere, which are termed deliquescent. Many salts have the property of crystallizing without water of crystallization; others, again, crystallize in different forms, according to the number of equivalents of water they contain. Biborate of soda, or borax, for instance, crystallizes in prisms or octohedra, according as it contains ten or five atoms of water of crystallization. The forms which crystals a ume are also influenced by the purity of the solution from which they are crystallized; for instance, iodide of pota ium a umes a prismatic form when crystallized from a neutral solution, but if from one containing carbonate of potash, the resulting crystals are cubical. As to the force causing C., we as yet know but little; all we know at present is, that electricity and light both accelerate C. If a weak voltaic current be pa ed through a solution of silica, it will gradually crystallize round the wires; and if camphor be exposed to the light, crystals will form thicker on the most illuminated side. Crystallize, v. a. To form into crystals; to cause to form crystals. -v. n. To be converted into a crystal or crystals; to unite, as the separate particles of a substance, and form a determinate and regular solid. Crystal logʼenic, Crystallogen'ical, a . Relating, or pertaining, to the production of crystals. Crystal log'eny, n. [Gr. krystallos , crystal, and genes thai, to be born.] The science of the production of crystals. Crystallographer, n . One who is versed in crystal lography. Crystallographic, Crystallograph'ical, a. Relating or pertaining to crystall raphy. Crystallographically, adv. In a crystallographic manner.