Ammolite is a rare, beautiful and valuable natural gemstone found in the Rocky Mountains in Canada and the United States. It consists of the fossilized shells of ammonites, which in turn are composed mainly of the mineral aragonite, the same material that makes up nacreous pearls, with trace elements of aluminum, barium, chromium, copper, iron, magnesium, manganese, silicon, strontium, titanium and vanadium. Ammolite is also known as aapoak, Blackfoot for small, crawling stone, calcentine, korite, ammonite shell or gem ammonite.

Ammolite was given official gemstone status in 1981 by the World Jewelry Confederation and the CIBJO The Colored Stones Commission. Ammolite is the official gemstone of the Province of Alberta and the City of Lethbridge. 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 and pearl.

Ammolite is considered the rarest organic gem material. It is a delicate and soft gemstone. On the Mohs Scale of Hardness, where talc is rated 1 and diamond ends the scale at 10, Ammolite is rated 4. 5 through 5.5. The price of gem quality Ammolite continues to rise as its popularity and the demand for this beautiful gemstone increases.

It抯 iridescent play of color, which is similar to opal, is shown in the fine specimens, mostly in shades of green and red, but other colors are possible. Unlike most other gems, whose colors come from light absorption, the iridescent color of ammolite, or the 揷olor play?comes from interference with the light that rebounds from stacked layers of thin platelets that make up the aragonite. The thicker the layers, the more reds and greens are produced; the thinner the layers, the more blues and violets are present. Red and green are the most common colors. When first mined, these colors are not extremely dramatic. This gem requires cutting and polishing in order to reveal the true color play.

The grading and the valuation of ammolite 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. There are also certain hues or shades of colors, like crimson or violet or gold, which are derived from a combination of the main or primary colors that are the rarest. The most valuable grades have approximately equal portions of three or more primary colors or 1? bright and even colors; with the lowest grades having one comparatively dull main color.

The way the colors play

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 still maintaining its play of color; the best stones can rotate 360 degrees while continuing to display the same intensity of color. Less valuable stones may show highly directional colors that are only visible within a narrow rotational range, down to 90?or less. Intermediate grades have ranges of 240?80?

Brightness of colors iridescence

The brightness of colors and their iridescence depends on how well preserved the nacreous shell is, and how fine and orderly the layers of aragonite are arranged. The quality of the final polish is also a factor. The "dragon skin" cracking usually lessens its value; the most prized ammolite is the sheet type and has broad, sheets of color similar to the "broad flash" opal.

Different Ammolite 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

Different Forms of Ammolite

1. Naturals are ammolite gemstones with just a polished finish and no other treatments. The original shale of the fossil backs them.

2. Doublets are cabochons that have been bonded to a backing.

3. Triplets are constructed of three layers. A dark gray wafer of natural shale (sits below a layer of Ammolite. On top, there is a calibrated cap of optical quartz or synthetic spinel.

How To Care For Ammolite Jewelry

Ultrasonic and steam cleaners should never be used for Ammolite jewelry. A good commercial pearl cleaner or a mild, warm natural soap solution with a soft cloth is recommended to gently clean your Ammolite jewelry.

Direct contact with chemicals, heat, perfume, acid, hairsprays, and many household chemicals can damage your Ammolite. As with any other gemstone, always use caution and general care.

I hope you have enjoyed reading this page and I hope I have been able to shed some light on some common Ammolite questions.