If you’re looking for a stone with a unique and beautiful look, chalcedony is definitely worth considering. This gemstone comes in a wide range of colors and varieties. Chalcedony is also very durable, making it an excellent choice for jewelry and other decorative objects.
This article will explore everything you need to know about chalcedony, including its physical properties, varieties, colors, and meanings. By the end, you’ll know whether this gemstone is right for you.
What Is Chalcedony?
Chalcedony (kal-sed-n-ee, kal-suh-doh-nee) is a form of microcrystalline quartz that is composed of fine, intergrown crystals of quartz and moganite. The crystals are usually so small that they can only be seen with a microscope.
In common trade, only the translucent, single-color types are usually classified as “chalcedony,” while the others are referred to under various names such as agate, chrysoprase, bloodstone, onyx, or jasper.
where does Chalcedony’s name originate from?
The word “chalcedony” comes from the Greek word “chalcedonios” which means “of Chalcedon.” This is likely a reference to Chalcedon, an ancient maritime town located in what is now Turkey.
Chalcedony was first described by Pliny, the Elder, a Roman naturalist, in his Naturalis Historiae, written around 77 AD.
What are the Physical Properties of Chalcedony?
Chalcedony is a gemstone that has a hardness of 6.5-7 on the Mohs scale. This makes it an ideal stone for crafting jewelry and other decorative items.
Chalcedony is a translucent, cryptocrystalline variety of quartz. As such, it shares many of the same physical properties as other types of quartz.
Chalcedony typically has a waxy luster and is translucent to opaque. It has a lower density than other quartz varieties (SG: 2.58–2.64). It is porous and can be stained to improve the color.
|Chemical name||Silicon dioxide|
|Color||white, blue, gray, colorless, multicolored|
|Hardness (Mohs scale)||6.5 – 7|
|Luster||vitreous to waxy|
|Transparency||Transparent to opaque|
Where is Chalcedony Found?
Chalcedony is found in a variety of places around the world. It is most commonly found in Europe, Africa, and North America.
List of major chalcedony deposits by country:
What Color is Chalcedony?
Pure chalcedony is white. However, it can also be found in a wide range of colors, including shades of blue, green, yellow, purple, pink, and gray. The color is caused by the presence of trace elements in the crystal structure. For example, manganese gives chalcedony a pink or purple hue, while iron oxides can give it a red or yellow hue.
Popular varieties of chalcedony based on their distinct colors:
Types of Chalcedony
Mineralogists know more than a hundred varieties of chalcedony, differing in composition, structure, and shade. But only a few dozen of them are used in jewelry and are of high value.
The varieties of chalcedony most commonly found in jewelry are:
|Agate||Multicolored banded variety is characterized by color bands in a concentric form or moss-like inclusions.|
|Carnelian||Translucent to semiopaque, reddish-orange to a deep burgundy color|
|Sard||Chalcedony with a reddish-brown hue and streaks of black|
|Chrysoprase||A clear quartz variety that ranges in color from pale apple green to blue-green, depending on the amount of manganese present|
|Bloodstone||Dark red to maroon in color, typically banded or spotted|
|Onyx||Banded black with a metallic sheen, often cut into geometric or animal forms|
|Jasper||Shades of brown, yellow, red, and green|
|Petrified Wood||Colorful agate that has replaced tree trunks and limbs|
|Chrome Chalcedony||A translucent, chromium-green variety of chalcedony similar to chrysoprase from Zimbabwe, Africa|
|Chalcedonyx||alternating strips or bands of gray and white|
|Sardonyx||a variety of chalcedony with a blue-green hue and black inclusions|
What Is Chalcedony Used For?
Chalcedonies of all varieties have been used in jewelry and gemstone carvings since ancient times. The earliest stone tools were commonly made of some form of chalcedony.
Uses Of Chalcedony in History
- The Egyptians used chalcedony as a building material, especially for temples and tombs.
- The Greeks used it in facial masks to cure diseases of the eyes, ears, and skin.
- Hieroglyphs in Ancient Egypt depicted a chalcedony ring on the hand of Ahmose Nefertari, the consort of Akhenaten.
- In the Middle Ages, it was used in the manufacture of agate buttons, combs, and bottles for perfume.
- The Egyptians used chalcedony to make glass. They believed that chalcedony brought eternal youth, so it gave their glass its green color.
- Chalcedony was popular in Victorian jewelry and ornaments.
- Chalcedony was a highly prized gem by ancient priests. It was a sacred material with lots of symbolism.
- It was a prominent stone in religious objects such as the chalice, the saint’s organ, the papal tiara, and baptismal fonts.
- It was commonly used to make crosses and crucifixes.
Uses Of Chalcedony In Modern Times
Modern uses of chalcedony are mainly related to its uses in the production of jewelry, figurines, utensils, and artistic objects, as well as scientific instruments, such as optical prisms.
Chalcedony Value and Price
Chalcedony can be a very affordable stone. However, location, color, size, and finish can greatly affect its value. Chalcedony prices range from a few dollars per carat to hundreds of dollars per carat. The most valuable colors are in the purple and blue-violet range.
The price of chalcedony is affected by:
- Location: Some locations are known for their high-quality chalcedony specimens. These specimens command premium prices.
- Color: Chalcedony occurs in many colors. However, the most valuable colors are in the purple and blue-violet range.
- Size: Large specimens are rare and command very high prices. Specimens with unusual shapes or patterns also command higher prices.
- Clarity: Most chalcedony is opaque and does not contain many smaller crystals. Specimens with clear areas or that contain large numbers of smaller crystals command higher prices.
- Finish: The finish on chalcedony specimens affects their price. Specimens that have been polished to a high-luster finish command higher prices.
Is Chalcedony Rare?
Chalcedony is a mineral that is found in numerous locations all over the world and is not rare. However, what is rare is a beautiful and unusual chalcedony specimen that exhibits intense color.
Chrysoprase displays a beautiful deep green color and remains one of the most sought-after varieties of chalcedony.
How Can You Tell If Chalcedony Is Real?
Due to the wide variety of colors and patterns in the chalcedony group, it can be difficult to tell real chalcedony from a fake. While there are several ways to identify real chalcedony, the easiest way is to buy chalcedony from a reputable dealer with a good reputation.
To help you make a more informed decision about buying chalcedony, here are some tips for identifying real chalcedony from fakes:
- Natural Colors: Chalcedony has natural and not-so-vibrant colors. Fake chalcedony is typically colored with paint or dye to bring its color closer to some of the most valuable bright colors.
- Scratch Test: Chalcedony usually has the same hardness as Quartz (7 on the Mohs scale) and is not easily scratched.
- Clarity: Real chalcedony is usually opaque and contains many smaller crystals. Fake chalcedony is usually clear. This can be determined by holding the piece up to the light; if the light source shines through the specimen, it is not a real chalcedony.
- Natural Veining Pattern: Translucent chalcedony can have natural veining patterns or banding. This natural banding or veining should be prominent with or without light. Fake chalcedony rarely has natural veining patterns.
- Transparency: Chalcedony is often translucent or semi-opaque to light. Fake chalcedony is usually transparent.
How to Clean Chalcedony?
Chalcedony should be cleaned with care. Using the wrong cleaning methods or cleaning materials can damage your stones and reduce their beauty. There are both mechanical and chemical methods of cleaning chalcedony.
Mechanical methods include using a lint-free cloth or a chalcedony polishing cloth. Chemical methods include using water and a mild detergent solution. Be sure to read the instructions on the specific product you are using before beginning to clean your stone.
Steps to Clean Chalcedony Jewelry:
- Use a soft microfiber cloth to gently wipe the chalcedony. Microfiber cloths are the softest material you can use on delicate stones like chalcedony.
- Avoid cleaning too hard or too often as this can cause abrasions that will bring to light some flaws in the gemstone.
- Use warm, soapy water and a soft toothbrush to gently scrub your chalcedony for a deeper clean. This method is effective for removing old polish and stains from your chalcedony.
- Dry your chalcedony with a lint-free cloth, and then buff it with a soft microfiber cloth to get a beautiful shine.
- Avoid using strong chemicals, steam, and ultrasonic cleaners to clean chalcedony.