This ammonite is spectacular!!!!  The accent stones are tsavorite, topaz black drusy quartz in 22k, 18, & 14k gold.  I will be hard to let this one go!  .

 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 gem, 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 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. Most commercial mining operations have been conducted along the banks of the St. Mary river, south of Lethbridge.
... 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. 

 The thumb nail pictures are some examples of color patterns found in ammonites.

• Ammonite
• Black drusy quartz
• Tsavorite
• Topaz
• 22k & 18k gold
• 14k gold