Fire Agate Gemstone Information
About Fire Agate - History and Introduction
Fire agate is a rare variety of layered chalcedony quartz which exhibits a fiery iridescent effect. It is a natural gemstone found only in the surrounding areas of the Southwestern United States and Northern Mexico. Iridescence is a unique optical phenomenon caused by light diffraction. As light passes through different layers of material, a prism effect causes light to separate into various spectral colors. With fire agate, the alternating layers are composed of limonite or goethite iron oxide and silica. It is the unique internally layered composition that distinguishes fire agate from any other variety of agate.
Fire agate was formed through volcanic activity that took place during the Tertiary Period, millions of years ago. Certain areas were subjected to extreme volcanic activity, which repeatedly caused hot water saturated with colloidal silica and iron oxide to seep into the cracks and cavities of rocks below the Earth's surface. As the solution cooled, the silicate and iron oxide began to grow layers of chalcedony, typically forming botryoidal; grape-like formations. Since it is the iron oxide that is responsible for the brownish color of fire agate, as the solution is depleted of iron oxide, colorless chalcedony continues to form, producing the typical brown and white rough fire agate commonly found today.
Identifying Fire Agate Back to Top
Fire agate is a limonite-bearing layered form of chalcedony or microcrystalline quartz with a botryoidal, or grape-like formation. Like other chalcedony quartz gemstones, fire agate has a hardness of 6.5 to 7 on the Mohs scale; a specific gravity of 2.59 to 2.67; and a refractive index of 1.530 to 1.540. It has no cleavage and can be identified by its silicon dioxide composition. It is distinguished from other agate by its remarkable iridescence caused by light diffraction, which is a consequence of its layered structure. The light diffraction results in reflections of light in various spectral colors unlike any other variety of agate.
Fire Agate Origin and Gemstone Sources Back to Top
Fire agate is found in only a few locations around the world. The most significant sources are Mexico and the Southwestern United States. Fire agate deposits are found in the areas between Kingman, Arizona and Needles, California, as well as the surrounding areas of the Colorado River.
Mexican fire agate comes from the mines of Calvillo in the state of Aguascalientes, Mexico. There are 23 known mines near the mountains of Calvillo. Fire agate can also found in San Luis Potosi and in Chihuahua, Mexico. The fire agate from San Luis Potosi is known only to exhibit golden fire; rainbow-like colors are extremely rare due to a distinct mineral composition.
Buying Fire Agate and Determining Fire Agate ValueBack to Top
Fire Agate Gemological Properties: Back to Top
Please refer to our Gemstone Glossary for details of gemology-related terms.
Fire Agate: Related or Similar Gemstones: Back to Top
Fire agate is just one of the many varieties of agate stone available today. Many agate variety classifications are based on optical properties, while others are classified based on inclusions, mining locality or geographic origin. Locality based trade names are generally only used by collectors. In many cases, a single agate specimen may even be classified under two or more different trade names.
Agate is a form of cryptocrystalline quartz. Cryptocrystalline quartz is one of two primary branches of quartz gemstones (macrocrystalline is the other). Both quartz branches share the same chemical composition but form with differing crystal structures. Amethyst, citrine and smoky quartz are a few of the more popular examples of macrocrystalline quartz gemstones.
Fire Agate Mythology, Metaphysical and Crystal Healing Properties Back to Top
Agate was used as gemstones by ancient Egyptians over 3,000 years ago, making it one of the oldest gemstones mentioned in recorded history. However, fire agate has only been available commercially since more recent times. Agate in general, is prized as a stone of prosperity, good health and longevity. It is associated with the protection of the elements and is believed to aid communication with all things in nature. Fire agate in particular has a calming energy that brings safety and security. It has especially strong grounding powers.
Fire agate can encourage healing, restoration and creativity. It can also improve self-esteem and emotional balance. Agate is a stone of protection and since biblical times, it has been believed to allow the wearer to weather storms. It is highly valued as talismans and amulets. Agate is also believed to help develop emotional balance and is thought to be able to strengthen stamina and endurance. Agate encourages generosity and responsiveness in those who wear it. Additionally, it is thought to possess the ability to balance the energy of the body, mind and spirit. Physically, agate is thought to quench thirst and alleviate fever. Alternative healers will place agate on the solar plexus region of those suffering from stomach illnesses.
Fire Agate Jewelry Back to Top
High quality fire agate can be as impressive in its play of color as fine black opal, and fire agate is much more affordable although it is significantly more durable. Fire agate is quartz with a hardness of 7 on the Mohs scale, so it is considered quite suitable for any kind of jewelry, including rings for daily wear.
Cutting fire agate is painstaking work and since very few pieces can be cut into traditional shapes and calibrated sizes, it is very rarely found in any mainstream jewelry. Owing to the variety of fancy freeform shapes, it is most often used for creating interesting pendants, pins or brooches.
Note: Buy colored gemstones by size and not by carat weight. Colored stones vary in size-to-weight ratio. Some stones are larger and others are smaller than diamond by weight in comparison.
Fire Agate Jewelry Care and Cleaning Back to Top
Fire agate is a variety of quartz. All quartz is considered to be quite durable compared to most other gemstones. Fire agate can be easily cleaned using warm soapy water and a soft cloth. Be sure to rinse it well to remove any soapy residue. Even though it has excellent hardness and durability, there are still a variety of other gems capable of scratching fire agate, including diamond, sapphire, spinel and topaz.
As with most gemstones, avoid the use of any harsh household chemicals including bleach and hydrofluoric-sulfuric acid. Most agate stones are quite porous, which allows them to be easily stained, through absorption of other chemicals and colors. Avoid prolonged exposure to extreme heat, as heating can permanently damage color. When storing, wrap your stones using a soft cloth and place them inside a fabric-lined box for added protection. Always remove any gems and jewelry before exercising or playing any sports.
- First Published: January-22-2014
- Last Updated: May-16-2017
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