AMMOLITE

... In 1981, ammolite became recognized by CIBJO, (the Colored Stones Commission.) It is the latest of only three new gemstones introduced in the last 50 years. It is also only one of three organic gemstones, (including amber & pearl.) It has been compared to opal and has a superficial similarity to the Austrian mineral lumachelle whose iridescence is also provided by the fossil ammonite carnites floridus. ... Ammonite shell is comprised primarily of aragonite, (the same mineral that makes up pearls,) with trace elements of aluminum, barium, chromium, copper, iron, magnesium, manganese, silicon, strontium, titanium and vanadium. ... Unlike most other gems, whose colors comes from light refraction, the iridescent color of ammolite comes from interference with the light that rebounds from stacked layers of thin platelets in the aragonite. Ordered thick stacks for red gems, less ordered thinner stacks for green and unordered, very thin stacks for blue ones. ... The layers are .5 - .8 millimeters thick before polishing and .1 - .3 mm thick after polishing. This is sufficiently thick and durable to be manufactured into jewelry ... Ammolite is also known as aapoak, (Blackfoot for small, crawling stone,) calcentine, korite, ammonite shell or gem ammonite. Ammolite is the fossil shell of the upper cretaceous ammonites: Placenticeras meeki, Placenticeras intercalare & Baculites compressus. ... Ammolite is only found in the Bearpaw formation that extends from Alberta to Saskatchewan in Canada and south to Montana in the USA. The best grade of gem quality ammolite is along high energy river systems on the eastern slopes of the Rockies in southern Alberta. ... 75 to 70 million years ago, this was the northwestern edge of the Bearpaw Sea, (also known as the Western Interior Seaway.) It was a shallow, warm water sea that teemed with life. One of the most prolific of its inhabitants was the ammonite that thrived in every ecological niche, from deep-water bottom feeders to jet-propelled predators. It also had the biggest brain of its age, these squid-like creatures had coiled shells with gas filled chambers that provided buoyancy and propulsion. They were a favored delicacy of the predacious marine reptile, the mosasaur. Sinking its teeth into the coiled shell, the crocodilian mosasuar would extract the ammonites squid-shaped body and devour it, discarding the empty shell which then sank to the sea floor. Settling on the sea bottom, the empty ammonite shell was buried in mineral rich sediment carried there by the rivers and streams from the young Rocky Mountains. Cataclysmic volcanic activity from the growing rocky mountains periodically covered huge areas with meters thick ash that settled slowly to the shallow ocean floor. The ash killed all life below and sealed their remains in an heavy, semi-impermeable layer of mineral rich clay, (bentonite.) ... Over time, the Bearpaw Sea area was buried over 4 kilometers deep in ash. Through many glacial periods, it underwent geological uplift and eventually surface exposure. High concentrations of iron and magnesium created a regionally unique condition, which led to sedimentary digenesis. This impeded the oxidization process that converts the aragonite of the ammonite shell to stable calcium carbonate, (CaCo2.) Today the lining of that shell has become one of the most unusual gemstones, Opalescent Aragonite. Colors ... Gemstone ammonite can be found in any color known in nature or the imagination of man. It can also have an infinite array of color combinations in every square centimeter. The higher grades will either have a very strong, bright single color, or contain a range of bright colors drawn from a color spectrum vaster than a rainbow. Lower grade gemstones will show less vibrant colors in a more limited range. Generally, red/green is more common than blue or purple, but there are certain hues, like crimson, violet and gold, that are very rare and in high demand. Iridescence ... The property that allows us to see the incredible play of colors across its surface is iridescence. The shell's surface is composed of closely packed, tabular, crystals of aragonite, with their c-axis oriented vertical to the shell surface. They are united into thin lamellae, (plates or scales.) ... The thickness of these lamellae is of the same scale as the wavelengths of the spectral colors that make up white light. Thus, when white light, (sunlight,) enters the regularly spaced thin layers of aragonite, diffraction occurs and flashes of spectral colors are seen. ... The plates of aragonite crystals vary in thickness. In addition, the trace elements are randomly arranged and interspersed with inclusions of organic material, (conchiolin.) These three factors determine the colors and intensity of the diffraction. The best ammonite shell will have brilliant, vibrant iridescence, continually dancing with changing colors as the angle of the incident light changes. Chromatic Shift ... The color of ammonite depends on the angle of light and the viewers perspective. Sometimes subtle and sometimes spectacularly dramatic, a chromatic shift occurs. Red will shift to green, green will shift blue, etc. This is called dichromatic. ... Some gem material will have the shift restricted to hues within the same primary color group. This is monochromatic. The best gem material has spectrochromatic shift, meaning the color will shift through the entire spectrum depending on light source and your angle of observation. Rotational Range ... Some material will not show strong, vibrant colors through 360 degrees of rotation. As other gems are rotated, the brightness decreases and darkens to black. This is due to the light wave diffraction being blocked by the organic inclusions in the aragonite. For a gemstone to be Graded AA it must show a brilliant color through 360 of rotation. Gem Forms ... Ammolite is sold in three forms: naturals, doublets and triplets. ... Naturals are free-form cabochons with a non-coated hand-finish. They are backed by the original shale of the fossil and can range in size from 10 carats to 6 inches across! Priced by carat weight the backing thickness should not exceed 1.5 mm. ... Doublets are free-form cabochons that have been bonded to a backing. ... Triplets are constructed of three layers. A dark gray wafer of natural shale (1) sits below a layer of Ammolite (2). On top, there is a calibrated cap of optical quartz or synthetic spinel (3). This assures that the Ammolite gemstone shows the most brilliant flash as well as being durable enough to be worn as every-day jewelry. Patterns Stained Glass - window panes Dragonskin - scales Cobblestone - regular, uneven rows Floral - flower petals Ribbon - long thin patterns Feather - tendrils Tin Foil - bright crinkle stack pattern Paintbrush - broad strokes Moonglow - inner glow, mono or di-chromatic Ripple - regular striation lines Pinfire - small plates of changing flash Sunset - red tinged landscape scenes Lava River - green with red rivers of lava Christmas Tree - green with red ornaments or freckles Suture Gem - suture or leaf pattern Nipplites - three dimensional rainbow eye or tubercle Ripple - regular spaced rainbow striations or ribs Banding - distinct color bands Stain - spreading color changes Lava Lamp - color globules Terrain - Aerial map CHEMISTRY Variable, may include aragonite, calcite, silica, pyrite, or other minerals CRYSTALLOGRAPHY Amorphous REFRACTIVE INDEX 1.52 - 1.68 HARDNESS 4.5 - 5.5 SPECIFIC GRAVITY 2.60 - 2.85 CLEAVAGE None, parting present HEAT SENSITIVE Yes ENHANCEMENTS Opticon and lacquer stabilization *Wearability is graded as Excellent, Very Good, Good, Poor, and Forget It! Care & Handling ... Naturals are best suited for brooches, pendants, or earrings. Triplets are best suited to rings. The care and cleaning of pearls also apply to ammolite. Ultrasonic and steam cleaners should not be used; rather, a commercial pearl cleaner or mild, warm soap is recommended, (to a maximum of 20 minutes.) Excessive heat, acids and some perfumes or hairsprays may cause damage or loss of iridescence. The cap will protect from scratches but care should be taken to avoid blows that could result in the separation of the bonded layers.



Product Image Item Name- Price
AMMOLITE CAB (DOUBLET ) 01fb

AMMOLITE CAB (DOUBLET ) 01fb

JustCabs is proud to offer this nice 17x23mm,25.25ct,5mm thick FreeForm Ammolite Doublet Cab. This Doublet has a Great Red,blue,green,even some gold color. This cab is nicer in person. Hard to get all the color in the picture.This cab has a great...
$125.00

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AMMOLITE CAB (DOUBLET ) 02fb

AMMOLITE CAB (DOUBLET ) 02fb

JustCabs is proud to offer this nice 13x19mm,12.80ct,5mm thick FreeForm Ammolite Doublet Cab. This Doublet has a Great gold,blue,green,even some red color. This cab is nicer in person. Hard to get all the color in the picture.This cab has a great...
$65.00

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AMMOLITE CAB (DOUBLET ) 03fb

AMMOLITE CAB (DOUBLET ) 03fb

JustCabs is proud to offer this nice 10x19mm,12.20ct,5mm thick FreeForm Ammolite Doublet Cab. This Doublet has a Great Red,green,lil gold and even more Red color. This cab is nicer in person. Hard to get all the color in the picture.This cab has a...
$85.00

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AMMOLITE CAB (DOUBLET ) 04fb

AMMOLITE CAB (DOUBLET ) 04fb

JustCabs is proud to offer this nice 23x25mm,27.65ct,5mm thick FreeForm Ammolite Doublet Cab. This Doublet has a Great Red,blue,green,even some gold color. This cab is nicer in person. Hard to get all the color in the picture.This cab has a great...
$166.00

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AMMOLITE CAB (DOUBLET ) 05fb

AMMOLITE CAB (DOUBLET ) 05fb

JustCabs is proud to offer this nice 11x20mm,7.30ct,5mm thick TearDrop Ammolite Doublet Cab. This Doublet has a Great green,blue,yellow,even some red color. This cab is nicer in person. Hard to get all the color in the picture.This cab has a great...
$40.00

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AMMOLITE CAB (DOUBLET ) 06fb

AMMOLITE CAB (DOUBLET ) 06fb

JustCabs is proud to offer this nice 19x32mm,28.15ct,5mm thick FreeForm Ammolite Doublet Cab. This Doublet has a Great Red,lil green,even some gold color. This cab is nicer in person. Hard to get all the color in the picture.This cab has a great...
$140.00

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AMMOLITE CAB (DOUBLET ) 07fb

AMMOLITE CAB (DOUBLET ) 07fb

JustCabs is proud to offer this nice 8x16mm,6.95ct,5mm thick FreeForm Ammolite Doublet Cab. This Doublet has a Great Red,blue,green,even some gold color. This cab is nicer in person. Hard to get all the color in the picture.This cab has a great...
$35.00

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AMMOLITE CAB (DOUBLET ) 08fb

AMMOLITE CAB (DOUBLET ) 08fb

JustCabs is proud to offer this nice 11x17mm,7.50ct,5mm thick FreeForm Ammolite Doublet Cab. This Doublet has a Great Blues and purple color. This cab is nicer in person. Hard to get all the color in the picture.This cab has a great polish,with a...
$40.00

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AMMOLITE CAB (DOUBLET ) 09fb

AMMOLITE CAB (DOUBLET ) 09fb

JustCabs is proud to offer this nice 13x16mm,9.30ct,5mm thick FreeForm Ammolite Doublet Cab. This Doublet has a Great orange,green,even some gold color. This cab is nicer in person. Hard to get all the color in the picture.This cab has a great...
$45.00

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AMMOLITE CAB (DOUBLET ) 11fb

AMMOLITE CAB (DOUBLET ) 11fb

JustCabs is proud to offer this nice 9x17mm,4.25ct,3+mm thick FreeForm Ammolite Doublet Cab. This Doublet has a Great Red,blue,green,even some gold color. This cab is nicer in person. Hard to get all the color in the picture.This cab has a great...
$21.00

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