chalcedony
chalcedony from france
red jasper or heliotrope ( bloodstone ) from India
mokaite jasper from Australia
red jasper from New Caledonia
green jasper from Brazil
heliotrope cabochon
cabochon of tinted blue chalcedony from Africa
chrysoprase oval cut in facets
chromiferous color zoning
Detailed sheet
chalcedony
Chalcedony: This is a term including microcristallines and cryptocrystalline varieties of quartz, which come from the Greek name of the famous city of Carthage “Karkêdon”. Extracted in Egypt and Syria, it has been used since ancient times for intaglios and cameos, an active trade with Carthage being established.
Its base color varies from blue to milky gray through pale mauve, it can be porous, cloudy translucent, blue fluorescent.
The Sardonyx, light brown, reddish brown to dark brown, but even, unlike the “sardonyx” which is zoned.
The Jasper, some integrating it within a particular family. If its name comes from a Greek word meaning speckled stone, in ancient times it meant something very different. Of variable and opaque colors, monochrome jaspers are exceptional, because rather colorful, striped, speckled, flamed, zebra. The Jasper hématoide is also called iron eye.
The Heliotrope, its name comes from what was formerly attributed to it : the possibility to change the color of sunlight when it was immersed in water (“Helios” for sun and “Trepo” for “I turn” in Greek). The ring of Gyges, who, according to Greek mythology, rendered invisible, wore a heliotrope. Its other name “bloodstone” is false because it is not a Jasper, and its English translation (“bloodstone”) has nothing to do with the German word “Blutstein” (blood stone ) which designates the hematite. It is Dark green with red dots, green due to inclusions of chlorite, and red due to iron oxide. In the Middle Ages it was used to represent the crucifixion with blood drops.
The Carnelian is translucent, its name comes from its orange color similar to that of a cornel (dogwood fruit). It was used in antiquity for intaglios and cameos.
The Chrysoprase, his name evokes the golden glow and the color of the leek-green variety of quartz whose fibers have a radial microscopic texture. Its color is due to the presence of inclusions of nickel but may deteriorate after a long exposure to sunlight. This is the most valuable chalcedony.
The mtorolite is a green Cr-chalcedony from Zimbabwe.
CHEMICAL CHARACTERISTICS
SiO2
silicon oxide, microcrystalline silica
PHYSICAL CHARACTERISTICS
Main color
red
Other colors
white, blue, brown, grey, yellow, green
all the existing colors
Color of streak
white
Luster
dull, greasy, waxy
Hardness
6.5 to 7.0
Density
2.57 to 2.65
Cleavage
none
Fracture
conchoidal
OPTICAL PROPERTIES
Transparency
opaque, translucent
jaspers are opaque, chrysoprase, carnelian and sardonyx are translucent
Refractive index
1.530 - 1.540
Double refraction
0.004
very weak
visible double refraction
No
Pleochroism
absent
Number of colors
1
Fluorescence
variable
sometimes blue to white, also green
CRYSTALS PROPERTIES
microcrystalline aggregates, botryoidal or reniform
crystals system
trigonal
OTHER INFORMATIONS
Astrological sign
Aquarius, Cancer, Capricorn, Gemini, Leo, Libra, Pisces, Sagittarius, Virgo
APPROACHING GEMS
Exploited
sites
It is found mainly in Brazil, the USA (California), India, Madagascar, Namibia, Sri Lanka, Uruguay, Zimbabwe. Sardonyx: it comes from Brazil, Egypt, Madagascar, India, Uruguay.
Jasper: it is known in France (Poitou, Vosges …), Australia, Brazil, Canada, Egypt, United States, India, Kazakhstan, Madagascar, Russia, Uruguay.
Heliotrope: extracted mainly in India (Deccan), but also in Brazil, Australia, China, the United States. !Carnelian: extracted in Brazil, India, Sri Lanka, Saudi, Iran, Spain, Uruguay. !Chrysoprase: it comes from Frankenstein, a deposit known since the fourteenth century and located in Poland (Upper Silesia), but it is now found in South Africa, Australia (New South Wales South), Brazil, United States (California, Arizona, Oregon), India, Kazakhstan, in New Caledonia, Saudi, Egypt, Japan, Madagascar, Russia (Urals), in Tanzania … as nodules or crack fillings in nickel deposits.
A variety of Jasper mixed with Chrysocolla is called “ parrot wing “ , because of its resemblance to the wings of a parrot.
use in jewelry
Carnelian: it is crafted into objects of art, cabochons, balls to necklaces.
Sardonyx: it is crafted into balls for necklaces, ashtrays …
Chrysoprase: used to make necklaces, objects of art, cabochons. Previously, it served as a decorative stone, as in the chapels of St. Wenceslas in Prague and Holy Cross at the Kalstein Castle (Czech Republic) or in the castle of Sans Souci in Potsdam (Germany). It is crafted nowadays into objects of art, cabochons, balls to necklaces etc. Frederick II of Prussia was a great lover of the Chrysoprase which he had cut cabochon oval with just one row of facets around, we call this cut as “ Frederick “.
The opaque variety, Jasper (red jasper, plasma green) is used to model objects of art (statues, bowls, vases …), mosaics, cabochons. Its cut and polishing are difficult because the layers tend to dissociate.
Heliotrope: it is manufactured into tables for signet rings or different objects (ashtrays, figurines, stamps …) cabochons, balls for necklaces.
Daily care
and precautions
Very easy to maintain, usually strongly resistant to household products. Be careful not to let it dry with drops of lime water, because drying the limestone remains in a thin coat and dulls the luster.
imitations and
treatments
Chalcedony: it is synthesized for scientific purposes, but it is worthless commercially and can be dyed.
Sardonyx: many are artificially dyed.
Carnelian: it is often forged from dyed agate or heat treated.
Heliotrope: some crude imitations in a dark green glass with red uniform spots are known.
Jasper can be dyed blue to imitate lapis lazuli.
Historical
healing properties
Chalcedony: in Tibet, this stone symbolizes the pure white lotus. In ancient times, people said it was enough to move their tongue on it to become a speaker. It is very sweet, positive and spreads calm emotions, soothing sorrow, the agitated (third eye chakra), it would be recommended for aggressive people (throat chakra), protects from poisoning (solar plexus chakra), enlightens the view, soothes hoarseness and preserves from travel hazards. It represents charity and, wore around the neck, it would chase the ghosts, remove melancholy and would provide a restful sleep. It corresponds to Sagittarius, Gemini, Capricorn and Cancer.
Sardonyx: it would bring cheerfulness, courage, strength to fight adversity. It stimulates the mind, avoid useless discussions, increase wealth, chase the bad dreams, would provide the friendship of women.
Jasper: once called “the mother of all stones,” it would convey the wisdom, the elemental force, the love of “Mother Earth”. Its virtues, according to Robert Berquem, are staunch the blood, preventing abortion, to promote childbirth. It would radiate permanently a protecting vital energy, purifying, invigorating. It would bring compassion and sensitivity, the will to do good and would develop eloquence. It would develop also the smell. Its associated zodiac signs are : Aries, Scorpio, Virgo, Cancer, Capricorn.
Heliotrope: it symbolizes constancy in love, reduce stage fright, shyness, inferiority complex. “It makes constant, glorious and reputable the one who wears it.” wrote Cornelius Agrippa (1727). It corresponds to Pisces, to Balance, and Taurus.
Carnelian: placed on the solar plexus chakra of angry and emotional people, it would have a soothing effect, absorbing energy instead of radiating it, by amplifying it, though it is not recommended for hypertensive patients. It would facilitate the concentration of thoughts and bring back to the present. Placed on the chakra of masculine sex it would have a beneficial effect. It corresponds to the zodiacal signs of Taurus, Virgo, Scorpio, Aries.
Chrysoprase: it symbolizes the acrimony, reason why it is tied to the apostle Thaddeus making incisive and bitter speeches towards the heretics. It would be the stone of the spring, the renewal of life, therefore ideal for pregnant women (solar plexus chakra) which would facilitate delivery (sex chakra), strengthening maternal love (heart chakra). The green opposes the red of dominating people but also reduces the inferiority complexes, gives self-confidence. It corresponds to the Cancer and Libra.
Other
Gems
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