Chalcedony Facts and Buying Guide

Chalcedony Facts and Buying Guide

by Sheweta Dhanuka

Chalcedony is a fibrous microcrystalline (also known as Cryptocrystalline) variety of silica that contains small crystals of quartz. It can be referred as name of the family that has many different varieties of gemstones in it.

Beautiful, abundant, durable, reasonably priced and unlimited variability are few of the genuine adjectives that describe the gemstone of Chalcedony group. Its name is derived from the name of the ancient Greek town known as Chalkedon in Asia Minor.
Chalcedony is a fibrous microcrystalline (also known as Cryptocrystalline) variety of silica that contains small crystals of quartz. It can be referred as name of the family that has many different varieties of gemstones in it. Few are recognized scientifically while the remaining ones are yet to be known. After the general characteristics information, the members of this family that are known in the gem trade market shall be introduced to the reader.

It is found in all parts of the world. It is a compact fibrous structure formed at the time of volcanic eruptions in sedimentary, igneous and metamorphic rocks. These rocks hold huge amount of this mineral. All its varieties are porous and vary from opaque to translucent. All these semi precious gemstones are quite tough so are given new shapes and cuts. Almost every gem belonging to this group is very friendly to the pockets of the buyer that means are priced moderately.

In ancient times, due to its vast availability and brilliant durability it was used for making man made weapons, tools and utensils. With the passage of time, as man became more and more civilized the uses of the stone began to change. Today, it is consumed widely as gemstone and ornamental stones. It is also used for making decorative items and storage boxes like pencil box, jewelry box etc. Large pieces are used for creating beautiful art pieces by efficient carving. Beautiful beads are made that form amazing necklaces and earrings.

Chalcedony is also used for making commesso. It is called as florentine mosaic too. It is a technique of creating pictures with thin, cut-to-shape pieces of brightly coloured, semi precious stones. Floral and landscape are the main subjects of these pictures. This art was developed in Florence in the late 16th century. Pictures made from this are used mainly for tabletops and small wall panels.


Now lets know about the Chalcedony group members in brief


It is the most distinctive and popular variety as it consists of varied colour band. The bands are concentric and curved. It is found in abundance in the cavities of eruptive rocks or the volcanic lava. It has its own varieties like Moss Agate, Dendritic Agate, Plume Agate and Fire Agate. These differ from one another due to the change in impurities in the composition like Denditic Agate contains manganese oxide impurities that form the fabrications and so on.


It is dark green coloured stone with bright red or brown spots. Spots can be multi coloured too. It is also called as Heliotrope. It possesses bright shinning and polished look.


When Chalcedony occurs in clear red colour and translucent then it is called as Carnelian.


It is translucent form of mineral consisting apple-green or plain bright green colour. Green colour occurs due to the impurity of nickel silicates or nickel oxide present in the composition. Prolonged exposure to sunlight or excessive heat might ruin the color and it can fade. It is priced maximum among all the members of this family.

Fossilized Petrified wood

It is wood that is been transformed into Chalcedony completely. It has wide range of applications of any gem material such as baroque jewelry, carved furniture, clock faces and decorative art pieces.


It occurs in almost all colours. Most preferred colours are red, brown or green and sometimes it might have streaks/spots of some other colour. It contains impurities that cause heavy pigmentation, which results in the formation of streaks or spots on the stone.


It is a semi precious striped gemstone with light and dark alternating bands in different colours viz. white, black, grey, red and brown. The colours occur in layers. It is a rich looking gemstone that can be easily afforded by a common man. When paired with pearls it makes fascinating jewelry pieces.


This variety is dull green in colour. These are carved into cabochons and beads like other varieties, making fine jewelry.
Plasma : It is semi-translucent and occurs in various shades of green. Bright emerald green coloured plasma gemstone is very popular. Sometimes it might consist of small red or brown colour spots throughout its mass. It has been used for years for carvings and mosaics.


It is orange or brown in colour with straight banding of white. Bands are the striped veins that can occur in any pattern. This stone is often carved into cameos or intaglios that are treasured most in Rome.


This gemstone is brownish to brownish-red in colour. It is transparent to translucent.

Blue Mist Chalcedony

This is last gemstone variety that belongs to this family of Chalcedony. It is tough, hard and durable gemstone that makes it excellent choice for the jewelry items to be worn daily. This stone always glows amazingly.
These were all the facts and information about the Chalcedony group and its gemstone members. Now we would through some light on the buying tips with respect to the general gemstone characteristics of this last variety that share the same name as that of the name of the group.


In the gemstone market the colour of this gemstone through which it is identified are blue-white, purple, buff, light tan, gray, yellow and brown. Different colour appears due to the presence of different impurities or some change in the chemical composition. All the colours are uniformly spread throughout the surface of the gemstone.


It is a massive gemstone consisting waxy or dull luster. It is translucent to opaque in nature. It does contain few fractures but due to its mass the inclusions are not visible through the naked eyes. Any cracks on its outer structure seldom occur. And even if they occur, those are removed during the necessary gemstone processing.


Its beauty is enhanced when cut in cabochon shape. However, it can be given any shape or style. Few common cuts are oval, square, round, pear etc. In modern jewelry this stone is used in new innovative shapes. Different carved shapes are also created like one of the designers gave it a beautiful carved shape of a leaf that looked stunning.

Carat Weight

This light coloured stone is found in large pieces. For the jewelry items any carat weight below five is easily available at an affordable price. For rings and earrings the ideal weight is between 2 – 4 ctw. Depending on the design may be one or more than one stone can be used. Further with the increase in the carat weight the price increases.


It is priced very reasonably. For this gemstone the price is dependent on carat weight and cut. Clarity and colour are not taken much into consideration while quoting the cost. However, new cuts and carved shapes may fetch little higher price. It is totally dependent on the designer’s expertise art of giving the creative look to the simple gemstone. More creative the work more shall be the price.


It is finely crystallized or fibrous quartz found in sedimentary rocks during the volcanic eruption. Almost all the states of United States produce this stone. Other countries are Uruguay, India, Madagascar, Myanmar (Burma), Mexico Brazil and Southwestern Africa.


This beautiful gemstone is widely used for making fascinating jewelry. Rings, earrings, pendants and bracelets can be made of yellow gold, white gold or silver. As it is mostly found in light colours so it is complemented more by the use of silver rather than yellow gold. And white gold being expensive may or may not suitable for everyone’s pocket therefore, is preferred less. Sleek silver wires are used for making fashionable and contemporary jewelry pieces that looks very attractive. However, 14K or 18K yellow gold is also used widely.

This gemstone is very well paired along with other semi precious stones like topaz, peridot, pearl, tourmaline, amethyst and so on. Bezel or prong settings can be used for holding the stone in the jewelry items, ensure the setting is perfectly done. For pendants spring-ring-clasps are more suitable as it can go in the chains of any width. Beads of this gemstone are also quite popular for different jewelry pieces.

Apart from the jewelry it is also used for making fancy decorative items like chandelier, boxes etc. It is even carved into cameos and intaglios. And also used for making sculptures. Sculpture made from one single stone is priced more than those made from more than one stone piece. Commesso pictures made from this stone are treasured too much in few parts of the world.


As such no specific precautions are required but general gemstone care should be taken for the lifetime retention of the beauty of gemstone. Sharp blows and scratches must be avoided. The gems, jewelry pieces and carved items must be protected from large temperature changes and harsh chemicals. The items must be cleaned from time to time with the luke warm soapy water and soft cloth. Clean the sculptures with a soft hand, any force or pressure from hand should not be applied. All sort of rough handling must be avoided.


It was believed to develop the emotional balance, stamina, kindness, generosity, responsiveness, receptivity, charity and friendliness. It was considered to heal the physical problems like fever, leukemia, eye problems etc. It has one unique property of balancing the energy of the human body, mind, emotions and spirit. In the gems market it is one of the most collected gemstone due to its splendid durability uses, price, variety and beauty.