Appraisal can be a complicated subject when dealing with fossil woods, as there are literally hundreds of popular localities worldwide, and one needs to acquire a proper working knowledge of what those localities produce and also, what the best from those localities look like. To give an accurate valuation of any fossil wood, each specimen must be scrutinized by several criteria, these criteria being drawn from known data from each given locality. Below are some of the more important attributes that can be used. This short list is drawn from my own methods for evaluating fossil wood, and is by no means meant to the "only way" - just to serve as a guide for those wishing to know a bit more about fossil wood valuation.
1)Quality: When evaluating a piece, the first thing to be addressed is the quality. Is your specimen solid and rock-like, with minimal fracturing? or is it porous, fractured and crumbling? A solid piece tells us that this wood will cut and polish without falling to pieces. Some fossil wood from Arizona can contain fractures, and these have become acceptable due to the compact nature of the material and of coarse their bright colors.
3) Interior pattern:
4) Interior color: Color can be a subjective issue when dealing with fossil wood, as many worldwide localities produce only earth-tones while others such as Arizona and Utah produce vibrant colors such as reds, yellows blues etc.. However, many rare and desirable species such as Cycads and Ferns are found mainly in earth tones and yet they can be more valuable than the brightest Arizona rainbow wood. Also, color can be of little importance when evaluating material from certain Washington and Oregon localities as here, earth tones prevail.
5) Size/ weight: This is how "rough" fossil wood is bought and sold. It can range in price from .10 cents a pound to $4.00 or more a pound.
6) Unusual features: This can be a branch extension, worm tracks, Knot holes, a double heart, an interior knot, mineral inclusions or even extremely vibrant and strong cell structure.