Ammolite is a rare and valuable opal-like organic gemstone. It is found along the eastern slopes of the Rocky Mountains of  North America.
It is made of the fossilized shells of ammonites, which in turn are composed primarily of aragonite, the same mineral that makes up nacreous pearls.
It is one of several biogenic gemstones; others include amber and pearl.

An iridescent opal-like play of color is shown, mostly in shades of green and red; all the spectral colors are possible, however.
The iridescence is due to the microstructure of the aragonite. The thicker the layers, the more reds and greens are produced; the thinner the layers,
the more blues and violets predominate. Reds and greens are the most commonly seen colors.

The ammolite deposits are stratified into several layers: the shallowest of these layers, named the "K Zone", lies some 15 meters below the surface
and extends 30 meters down. The ammolite within this layer is usually cracked - this is the crush material. It is the most common. Beginning twenty meters
below the crush material is the "Blue Zone"; ammolite from this zone, which extends 65 meters. This is the sheet material; due to its depth it is rarely mined.
It is also much less fractured, and therefore the more valuable type of ammolite.

 

Gemological facts

Composition of Ammolite: Calcium Carbonate with 3 to 4% trace minerals.

Mineral type: Aragonite

Refractive index: 1.52 to 1.67

Specific gravity: 2.8 to 3.5

Hardness: 4 to 4.5

 

Ammolite can be cut into:

• NATURAL STONES: a layer of ammolite is naturally bonded to a matrix or rarely in a solid two sided piece of gem
• DOUBLETS: a polished layer of ammolite bonded to a hard shale back
• TRIPLETS: a layer of ammolite between a backing and a hard spinel or glass

Difference between Ammonite and Ammolite is that ammonite were animals and ammolite are gems.

Ammolite was recognized as a semiprecious stone until 1981. Than it was recognized as a gemstone by CIBJO, the Colored Stones Commission.

 

Grading

There is still not a recognized grading system but most of the people consider as following

Stones with three colors, and high brilliance are graded as AAA: they display multiple colors at any angle and the finish is flawless.

Two colors stones are graded as AA.

One color stones are graded as A.

So we can say that Ammolite grading is based on the number of colors present and the brilliance of the stone. "Crushed" or "Sheet" material is not important for the grade.

 

Care & Cleaning

Ammolite should be cleaned with a soft, dry cloth. Doublets and triplets can be cleaned with a soft, damp cloth. Ammolite should not be cleaned in steam or ultrasonic device.
Keep Ammolite away from harder jewelry that may damage it.

 

Feng Shui

Ammolite is known as the Seven Color Prosperity Stone in Feng Shui, and is highly prized for its ability to improve chi, or energy flow.
It is considered mystically for general good health, stamina and high energy. Ammolite is believed to enhance wisdom, wealth and enlightenment and is a tool for deep meditation.
Ammolite is said to radiate strength and to  have the power to transform negative energy into positive energy.
Ammolite is also called buffalo stone to the Blackfoot Indians, with ability to help them hunt and capture buffalo, and for the luck and stability that it brings wearing it.
Considered a stone of protection.