Chalcedony

“ A slow ride of eight miles placed us in a safe gorge draining a dull-looking, unpromising block. Here we at once found, and found in situ for the first time, the chalcedony which strews the seaboard-flat. This agate, of which amulets and signet-rings were and are still made, and which takes many varieties of tints, lies in veins mostly striking east-west; and varying in thickness from an inch to several feet. The sequence is grey granite below, the band of chalcedony, and above it a curious schistose gneiss-formation. ”

“ Similarly contorted fibres occurring in chalcedony do not exhibit the crystallized structure, but appear to consist of very minute or of invisible particles, or even of a mere colour diffused in that particular form. At times the coloured fibre contains grains of chlorite attached to its sides or interspersed through its course, thus emulating the imbedded seeds or jointed appearance of real confervæ, and I have reason to think often mistaken for them. ”

“ It is worthy of remark that in almost all the specimens of chalcedony which appear to contain aquatic confervæ, not only the vegetable structure is perfectly preserved, but the plant, however light and yielding its texture, is disposed in as free a manner as if still living and floating in the water which was its native element. ”

“ In these specimens (brought from Egypt) distinct grains of green matter may be observed independent of the general green stain which pervades the stone; and this probability is rendered still stronger from the colour and appearance which is occasionally assumed by the more transparent flinty matter associated with the chalcedony, the latter acquiring from the chlorite the aspect of heliotrope, while the more transparent parts put on the semblance of plasma. But of a substance so rare it is necessary to speak with hesitation. ”

“ Some class agate, onyx, sardonyx, plasma and carnelian together as varieties of chalcedony, while others consider chalcedony a simple variety. The chalcedonic varieties of quartz agree in having a fibrous structure and in being somewhat softer (hardness 61⁄2) and somewhat lighter (specific gravity 2.6) than crystallized quartz. They also break with more difficulty than quartz, being very tough. The varieties differ among themselves, chiefly in color. ”

“ Busts and heads in full and bass relief were executed by the Romans on chalcedony in the grandest style; the finest specimens of these that we possess are the Marlborough "Medusa," and the bust of "Matidia," supported on a peacock, and three inches high. The chalcedony was supposed to cure lunatics, and make them "amiable and merry."
The agate was an object of the most fanciful delusions to the ancients. Orpheus says, "If thou wearest a piece of the tree-agate on thy hand, the immortal gods shall be pleased with thee ”

“ Carnelians and sardes are only color distinctions of chalcedony; and the immense family of agates, including the onyx and sardonyx, is more or less composed of chalcedony, disposed in layers, regular or irregular, and combined with other forms of quartz, such as amethyst, jasper, etc. This latter name is applied to an aluminous variety of quartz: it is opaque, and has a less crystalline appearance than ordinary quartz. It is very varied in color: some beautiful red, brown, and green-banded stones are obtained in Siberia, in Egypt, and elsewhere. ”

“ Flint is an impure brown chalcedony, usually forming concretions. The color is due to organic matter. Flint is mostly found in limestone or chalk, and the concretions are the result of the small particles of silica scattered through the 107 rock being dissolved, and then reprecipitated about some organic center. Generally the silica was obtained by the dissolution of small fossils, like the shells of diatoms or sponge spicules. ”

“ The chalcedony was not inserted in the high-priest’s breastplate, but instead the carbuncle, of which no mention is made here. It may well be, however, that the author designated the carbuncle by the name chalcedony. Andrew, then, can be likened to the carbuncle, since he was splendidly illumined by the fire of the Spirit.
The emerald, which is of a green color, is nourished with oil, that its transparency and beauty may not change; we conceive this stone to signify John the Evangelist. ”

“ In addition to the crystalline form, silica is freely deposited in an amorphous or cryptocrystalline form which has the same properties as quartz, except the crystal faces. This is called chalcedony, and it occurs in seams, cavities and free surfaces. When the surface of a chalcedony deposit is free it has a waxy luster. It is generally very brittle and breaks in a peculiar splintery manner. Like quartz it also has a great many varieties, according to the impurities present. ”

“ The solution of the latter question may be, that different genera of organic remains afforded centers that attracted the silex with unequal force, and that this will in some degree explain the phenomenon so common in the chalk formation, that bodies allied to the genus spunge and alcyonium, are most frequently preserved in flint and chalcedony, whilst shells and other bodies, which in their natural state were more calcareous, generally have their form retained by chalk or calcareous spar. ”

“ We find that no vesicle wants its coating of this earthy mineral. The coating received, however, one-half the doors shut, while the other half remained agap, and filled with green earth entirely. Next followed a series of alternate infusions of chalcedony, jasper, and quartz; many doors opened and received some two or three coatings, that form around the vesicles skull-like shells of agate, and then shut; a few remained open, and became as entirely occupied with agate as many of the previous ones had become filled with green earth. Then an ample infusion of chalcedony pervaded the mass. ”

“ The outer surface of an agate, freed from its matrix, is often pitted and rough, apparently in consequence of the removal of the original coating. The first layer spread over the wall of the cavity has been called the “priming,” and upon this basis zeolitic minerals may be deposited, as was pointed out by Dr M. F. Heddle. Chalcedony is generally one of the earlier deposits and crystallized quartz one of later formation. ”

“ It is perhaps superfluous to say that nodules of chalcedony, often hollow and containing crystallized quartz, are occasionally found in the trap rocks of Sky, since they are of such common occurrence in this substance. The cavities are sometimes, in addition, sprinkled with crystals of stilbite, of analcime, and of chabasite.
Of those mineral substances which are the least frequent in trap rocks, steatite occurs in considerable quantity; it is tender, and always of a greenish dirty hue. It is sometimes found in very small nodules ”

“ By comparing the account of the termination at New-Haven (Bruce's Journal, v. i. p. 139.) with that now published, of the termination at or near Deerfield, it will be seen that the geology and imbedded minerals are very similar. At East-Haven, (one of the branches of the greenstone of New-Haven, and within from three to four miles of the latter town,) chalcedony is often found, sometimes imbedded in the trap, (but perhaps more frequently loose among the fallen stones,) which, although in [135] small pieces, is as perfect in its characters as the chalcedony of the Feroe Islands. ”

“ A golden spell lingers around the scene, an influence that penetrates the soul.
Clara Hill.
74 QUARTZ.
The crypto-crystalline (obscurely crystalline) varieties of Quartz are many. The following may be named as the most important: Chalcedony, carnelian, sard, chrysoprase, prase, plasma, bloodstone, agate, onyx, sardonyx, jasper, basanite, flint and hornstone. The distinctions between the different varieties are loose and are differently stated by different authorities. ”

“ This amygdaloid accompanies the larger masses of green chalcedony, and seldom extends many inches beyond them. The great masses are either in the form of irregular nodules, reaching from the size of an egg to that of a man's head, or they resemble short veins, of which the opposing sides are flat, and somewhat parallel, and which might perhaps more properly be called angular nodules. Their colour is as various as their other external characters, but the most frequent varieties are comprehended in the following list. ”

“ This stone includes a number of varieties such as carnelian, sard, agate, catseye, prase, plasma, heliotrope, chrysoprase, moss agate, onyx, sardonyx, hornstone or Chert, and flint. Chalcedony is classed under the great Silica family. It is translucent, waxy, white, pale grey, light brown or bluish.
161The Blue Chalcedony is identified with the ancient Sapphirine—a stone confused with our sapphire. Mr. ”

“ Fig. 1. [1] This figure is given for the purpose of explaining the mode in which the fibrous disposition of chlorite is effected. The crystallized arrangement which is here so visible is generally observed in those chlorite fibres which occur in transparent quartz. I I have never observed it in chalcedony, yet there is little doubt that a similar disposition is equally the cause of the fibrous appearance so common in the specimens which have been figured in the former plates, the chief differences consisting in the smaller size and less perfect crystallization of the chlorite scales. ”

“ The metallic arborizations emulating the vegetable form which occur in the fissures of many stones, and the similar well-known figures in the chalcedonies distinguished by the name of mochas, with the lively though superficial resemblance they bear to plants, have led to the hasty conclusion that all these appearances were of a metallic nature, and have probably prevented that accurate investigation of them which they deserved. ”

“ And, for reasons which you will hardly understand, men are beginning now to believe that the chalk has never ceased to be made, somewhere or other, for many thousand years, ever since the Winchester Downs were at the bottom of the sea: and that “the Globigerina-mud is not merely a chalk formation, but a continuation of the chalk formation, so that we may be said to be still living in the age of Chalk.” ”

“ It is only when we arrive at the chalk measures that we find an "abundance" of animal life. Recent investigations have shown, that chalk is mostly composed of shells in every stage of change, some perfect, some broken, and still others decayed into an impalpable dust. ”

“ When we consider that the remains of more than three thousand distinct species of aquatic animals have been discovered among the fossils of the chalk, that the great majority of them are of such forms as are now met with only in the sea, and that there is no reason to believe that any one of them inhabited fresh water—the collateral evidence that the chalk represents an ancient sea-bottom acquires as great force as the proof derived from the nature of the chalk itself. ”

“ The perfect state of the surfaces of the chalk fossils proves also that this deposition proceeded from the surrounding fluid, and that it was not derived from the immediate action of any chemical agent, on the shells and other calcareous coverings of the animals living at the bottom of the sea. In the fossil animal bodies found in chalk, not the least diminution of the sharpness of their ridges or points is observable, nor is the least dulness of the delicate lines and embossments of the crusts, or of the spines of the echini, to be detected. ”

“ Dalechamps is of opinion that some person has here substituted the Latin “Aurei cornus,” for the Greek name Chrysoceras.
2348 Hence, according to Strabo, Chalcedon obtained the name of the “City of the Blind,” the people having neglected to choose the opposite shore for the site of their city. Still, however, a kind of pelamis, or young tunny, from this place, had the name of “Chalcedonia,” and is spoken of as a most exquisite dainty by Aulus Gellius, B. vii c. 16.
2349 Aristotle, Hist. Anim. B. viii. c. 16; Ælian, Hist. Anim. ”

“ And utterly unbearable grief surged over Chalciope’s soul for fear at what she heard; and then she replied: “Yea, I myself too have come to thee in eager furtherance of this purpose, if thou wouldst haply devise with me and prepare some help. But swear by Earth and Heaven that thou wilt keep secret in thy heart what I shall tell thee, and be fellow-worker with me. I implore thee by the blessed gods, by thyself and by thy parents, not to see them destroyed by an evil doom piteously; or else may I die with my dear sons and come back hereafter from Hades an avenging Fury to haunt thee.” ”

“ Infinitesimal specks, often so minute as to appear only as fine dust to man’s unaided sight; yet real organic remains, each one of which has been the home of an active animal.
A lump of chalk is a mass of densely packed [p. 139] tiny fossil shells, more or less crushed and broken. It has been reckoned that a cubic inch of chalk probably holds at least one million shells.
Try to imagine what this means. The work of the Ocean in building solid sandstone, from unnumbered myriads of myriads of grains of sand, is marvellous enough. But here we have something far more wonderful. ”

“ But what shall we say when the investigations of the microscope have lately revealed to us that these mountains of chalk, instead of being formed of mere inert matter, are, on the contrary, mighty congeries of decayed animal life,—the white apparent particles, of which the chalk masses are composed, being each grain a well-defined organized being, in form still so perfect, their shells so entire, and all their characteristics so discoverable, as to cause no doubt to naturalists as to the species in the animal economy to which they belonged. ”