How do you know if what you are looking at is really a high quality Ammolite stone?
That's a great question! Unlike other gemstones, Ammolite quality is not based on the 4 C's (color, clarity, cut, and carat/size). Although there are some similarities.
Color characteristics: it is important to know that one of the basic characteristics of Ammolite is that it can have what is called a chromatic shift of color as it is turned or tipped in the light. Reds will change to greens, yellows to orange, and greens to blues and purples. (In this way, it is very similar to looking at high grade / broad flash opal - where the colors change as the stone is tipped or turned.)
Another characteristic of this fossilized stone is that it can have a shattered look to it. This is commonly called "dragon scales". It is absolutely gorgeous! But this is a matter of preference - some customers really like this look while others prefer the more solid look.
Multiple Colors: Although the colors can shift, a stone is more valuable if it shows multiple colors at a time (like bands or stripes of several colors). However, I have discovered that this aspect of value greatly depends on the individual who is purchasing the piece. While the standard of quality may say that multiple colors defines a higher quality stone, many people prefer a stone that is a solid single color. Ruby red and emerald green stones seem to be the most popular single color stones. (Customers also really like blues, but blue Ammolite is very rare in the Utah deposits, so very few of those have been sold.)
Amount of gemstone vs. host rock: high quality stones have the Ammolite shell solid across the entire surface. Lower quality stones have portions where the host rock shows through - so there are places where the bright Ammolite color is missing or absent. One thing a few artists will do is use smaller pieces of Ammolite and create a mosaic of color on a host stone. These can be absolutely beautiful pieces, but they are less valuable than a solid piece of Ammolite of the same size.
Size: As with other gemstones, the larger the piece of Ammolite the greater the value. But again, this is tempered by the amount of gemstone vs. the host rock.
Being that Ammolite is a fossil, each piece is unique and if they are from the USA, they are also extremely rare. But when making a purchasing decision, regardless of what the "rules" may say, the most important thing is that you buy something that you really like and enjoy!
Find out more at UtahSeafireGems.com.