Ammolite



ammolite Ready to set

Contents
About Ammolite – History and Introduction
Identifying Ammolite
Ammolite Origin
Buying Ammolite
-Treatments
Ammolite Gemological Properties
Ammolite – Similar Materials
Ammolite – Metaphysical Powers
Ammolite Jewelry Ideas
Ammolite Care
How is Ammolite Graded?


Ammolite is an opal-like organic gemstone found only in southern Alberta, Canada. It`s made from the fossilized shells of Ammonites. Ammolite was given official gemstone gemstone status by the (CIBJO) World Jewellery Confederation in 1981, the same year commercial mining of Ammolite began. The City of Lethbridge designated Ammolite their official gemstone in 2007.

About Ammolite – History and Introduction
Ammolite, often referred to as Ammonite, is arguably one of the rarest gemstones on earth. Ammolite belongs to a small group of organic gemstones, which also includes amber, coral, jet and pearl. Ammolite is composed of the fossilized shell remains of Ammonites (primarily aragonite), which is the same mineral that makes up nacreous pearls. Ammolite’s highly desirable, opal-like iridescent play-of-color typically occurs in shades of green and red, but all of the spectral colors are possible.

Ammolite’s iridescence is a result of aragonite’s unique microstructure, making it different than most other gemstones with iridescence. Typically, iridescence is a result of light absorption, but ammolite color is a result of light interference rebounding off thin layers of platelets, which are part of aragonite’s organic structure. Ammolite is sourced primarily from one location along the eastern slopes of the Canadian Rockies. In 1981, mining for ammolite escalated to a commercial level and during this time, the World Jewellery Confederation (CIBJO) declared ammolite an official variety of colored gemstone. In 2004, Alberta, Canada declared ammolite as its provincial gemstone and in 2007, the City of Lethbridge also declared ammolite to be its official gemstone.

Ammolite is also known as ‘aapoak’, which originated from an Indian Kainah word, meaning “small, crawling stone”. Other trade names include gem-ammonite, korite and calcentine. Korite International mining company is the world’s leading commercial provider for gem quality ammolite. The term ‘ammonite’ was originally used to describe the spiral shape of the fossilized shells, which closely resembled the shape of ram’s horns.

Ammolite often has a flaky or “dragon skin” surface. To an extent, this is normal, but excessive scaling will reduce ammolite’s value. Almost all ammolite gemstones are assembled through a ‘layering’ enhancement. Layering is common in the gem trade and it is most often seen with precious opal in the form of doublets or triplets. Layering treatments enhance durability and in most cases, can also enhance color. Many specimens are stabilized by impregnation of polymer, epoxy or resins. Without enhancements, ammolite is far too fragile for use in jewelry. Pure strips of ammolite are available but almost all include some host rock matrix. Top grade ammolite stones should not show any visible matrix. Ammolite sources and deposits are expected to be depleted and exhausted within the next twenty years.

Identifying Ammolite
There are a few gemstones that closely resemble ammolite. The best examples would be Australian Black Opal & Mexican Fire Agate.

Ammolite Origin
While sources of Ammonite do exist in several locations around the world, Over 90% of the world’s supply of Ammolite comes from one place, Alberta, Canada. Most commercial mining operations have been along the banks of the St. Mary’s River, just south of Lethbridge, Alberta. About half of all Ammolite deposits are located within the Kainah (Kainaiwa) reserve. Korite International founded in 1971, has been the world’s leading provider for gem quality Ammolite. The company maintains an agreement with the Kainah (Blood) tribe, with Korite International paying the tribe royalties based on how much land the company has mined. If the current production rate of fine Ammolite continues, Ammolite mines are expected to be completely worked out within the next 20 years.

Buying Ammolite

Gemstone quality
The quality of gem Ammolite is communicated via a letter grade system, from most desirable to least desirable: AA; A+; A; and A-. However, this system is not yet standardized and some vendors may use their own systems. The grade and therefore the value of an ammolite gemstone is determined by the following criteria:

The number of primary colors
A large array of color is displayed in ammolite, including all the spectral colors found in nature. Red and green are far more common than blue or purple due to the latter’s fragility (see properties). There are also certain hues, like crimson or violet or gold, which are derived from a combination of the primary colors, that are the rarest and in highest demand. The most valuable grades have three or more primary colors or 1–2 bright and even colors, with the lowest grades having one comparatively dull color predominant.

The way the colors “play” (chromatic shift and rotational range)
Chromatic shift is how the colors vary with the angle of viewing and the angle of light striking the gemstone. In higher grades this variation is almost prismatic in its scope, while lower grades show very little variation. Rotational range is how far the specimen can be turned while maintaining its play of color; the best rotate 360 degrees uncompromised, while lesser stones may exhibit highly directional colors that are only visible within a narrow rotational range, down to 90° or less. Intermediate grades have ranges of 240–180°.

Brightness of colors (iridescence)
The brightness of colors and their iridescence is essentially dependent on how well-preserved the nacreous shell is, and how fine and orderly the layers of aragonite are. The quality of the polish is also a factor. The “dragon skin” cracking usually hinders its value; the most prized ammolite is the sheet type that has broad, uninterrupted swathes of color similar to the “broad flash” category of opal. The matrix is not visible in finer grades, and there should be no foreign minerals breaking up or diminishing the iridescence.

The thickness of the ammolite layer is also an important factor: after polishing, the ammolite is only 0.1–0.3 millimeters thick. The rarest and most valuable are thick enough to stand alone, with only a thin portion of its original matrix (not exceeding 1.5 mm); but the vast majority require some sort of supportive backing. Other treatments are also commonly undertaken; all other factors being equal, the less treatment an ammolite gem has received, the more valuable it is. Calibrated stones—that is, stones fashioned into standard dimensions that will fit most jewelry settings—may also command a higher price.

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 diamonds by weight in comparison.

Treatments
Although fully mineralized and containing no water—and therefore not subject to dehydration and subsequent crazing as seen in opal—ammolite is often damaged due to environmental exposure. The thin, delicate sheets in which ammolite occurs are also problematic; for these reasons, most material is impregnated with a clear epoxy or other synthetic resin to stabilize the flake-prone ammolite prior to cutting. Although the tessellated cracking cannot be repaired, the epoxy prevents further flaking and helps protect the relatively soft surface from scratching. The impregnation process was developed over a number of years by Korite International in partnership with the Alberta Research Council. Impregnated and epoxy-coated ammolite first entered the market in 1989 and the treatment significantly increased the availability and durability of the gem.

Because the Ammolite layer is usually mere fractions of a millimeter in thickness, most ammolite gems are in fact composite stones: these usually take the form of two-part doublets, with the ammolite layer adhered to a dark backing material. This is usually the matrix or mother rock from which the ammolite was quarried; black onyx or glass could also be used as backing. In composites where the ammolite layer is exceptionally thin, a third component is used: this constitutes a triplet, with a durable and transparent convex topping piece. This cap may be either synthetic spinel, synthetic corundum, synthetic quartz, or in lower-end productions, glass. The convex cap acts as a lens and has the effect of enhancing the ammolite’s iridescent display.

The detection of these treated and composite stones is relatively simple via inspection with a loupe; however, certain jewelry setting styles—such as those with closed backs—can complicate things. A triplet can be identified by inspecting the stone in profile; the top of the stone can then be seen to be domed and transparent, with no play of color. If the dome is made of glass, bubbles, swirl marks, and scratches may be present; the harder synthetic materials are optically flawless.

Although the vast majority of commercial-grade ammolite has been treated in some way, a small fraction of production requires no treatment other than cutting and polishing. Ideally, any treatments should be disclosed at the time of sale.

Ammolite Gemological Properties

Chemical Formula: Calcium carbonate (CaCO3); 3-4% variable mineral traces).
Crystal Structure: Orthorhombic
Color: Gray-brown, multicolored iridescence
Hardness: 4 on the Mohs scale (varies in composition.)
Refractive Index: 1.52 – 1.68
Density: 2.75 – 2.80
Cleavage: Pinacoidal
Transparency: Opaque
Double Refraction / Birefringence: 0.155
Luster: Greasy to dull; vitreous to resinous
Fluorescence: Ultraviolet light – mustard yellowish

Ammolite – Similar Materials
Most Popular Similar Gemstones:
Labradorite, precious opal, pearl, coral, amber and jet are the most common related gemstones.

Lesser Known Similar Gemstones:
Fire marble, fossilized clam, snail shell, spectrolite and abalone shell are lesser-known similar gemstones.

Ammolite – Metaphysical Powers
feng_shui_colorsAmmolite powers and metaphysical beliefs can be traced back through many centuries. Although ammolite is relatively new commercially, native tribes have been using ammolite for hundreds of years. The Blackfeet Indians named ammolite the ‘Buffalo Stone’, because they would find ammolite fragments washed-up on river banks, often with silhouettes reminiscent of buffaloes. Buffaloes represented wealth, health, power and stamina. Blackfeet tribesman believed ammolite possessed strong healing powers and often mixed the gem into medicines.

After ammolite was introduced to the rest of the world in the 1990s, ammolite became very popular among practitioners of feng shui. It was known as an “influential” stone. It was believed that ammolite had the power to enhance and detoxify the body with “chi”. It was later given the name of “Seven Color Prosperity Stone”. Each ammolite color influenced its wearer with a different “chi” or energy. Ancient Egyptians named the fossil after one of their gods, Ammon, because ammolite resembled the shape of ram’s horns. Ammonite was highly prized by Egyptians, Romans and Ethiopians alike. Ammolite was worn in the belief that prophetic dreams would come to them, and it would help with deep meditation.

Other ammolite powers include the ability to change negativity into flowing energy. It is thought to ease childbirth, reduce depression and relieve harmful thoughts and patterns. Since ammolites are fossils of once living creatures, they are linked to the fifth element, Akasha. Ammolite is also the stone of Aquarius and is assigned to the first (root/base) chakra.

Disclaimer: Metaphysical and Alternative Crystal Healing Powers and Properties are not to be taken as confirmed advice. Should you have any medical conditions, please see a licensed practitioner. This information is not to replace the advice of your doctor. Gemstone Nation does not guarantee any claims or statements made and cannot be held liable under any circumstances.

Ammolite Jewelry Ideas
Ammolite deposits are quite rare and only 50% of all finds are suitable for jewelry. Ammolite stones have been used as amulets for a very long time. Ammolite is usually fashioned into freeform shapes and mounted in silver or gold. The colors are best highlighted with clear crystal accents such as spinel.

Even though ammolite is typically layered as doublets or triplets, they are still very fragile. Therefore, ammolite is best suited for use in pendants, earrings or brooches. Ammolite gemstones can be worn as rings, but only when they are layered into triplets. Spinel is most popular for creating ammolite triplet cabochon rings. Canada is the number one source for creating and trading ammolite jewelry. Artisans often sell ammolite jewelry to tourists visiting Banff National Park. In the United States, ammolite is very popular among the Zuni tribe and other Native American craftsmen.

Ammolite Care
Like all organic gemstones, caring for ammolite requires extra attention. Ammolite can be cleaned with warm water and a soft cloth. Mild soap or detergent can be used if needed, but avoid harsh chemicals, including bleach, perfume or hairspray. Excessive heat and acid can weaken stability and iridescence. Though triplets are slightly more durable, the same level of care should be taken for all ammolite. Avoid hard blows, because it can cause damage and separation of doublet or triplet layers. Ammolite should be stored separately from other stones because it can be easily scratched by other gems. A silk bag, soft cloth or velvet-lined box is ideal for use when storing ammolite.

How is Ammolite Graded?
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AA Bright vivid colors, sharp and clear under grading lamp. Vivid with natural light. Color spread evenly throughout the gemstone. Three or more crisp colors. Good color change when gemstone is turned.

A+ Reflects light readily. Vivid colors under grading lamp. Good color in low light. Distinct colors with some inclusions that do not detract from beauty of the gemstone. Colors easy to discern. Two or more colors.
A Good colors under grading lamp. Definite bright patches of color, some larger grey/brown patches. Some color extinction with blue.
A- Colors not as distinct. Inclusions may distract from vividness. Faint color. Less brilliant overall appearance with some flashes of color overall. Yellow/brown tone.

AAA or Imperial stones are very rare. Less than 1/2 of 1% of Ammolite are of this composition. The AAA grade Ammolite is solid gemstone throughout compromised of several intense colors. These rare Imperial jewels are sought after by collectors and leading jewelers around the world and demand a premium price.

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