Gembone is dinosaur bone with the interior structure replaced by quartz.  It comes in all colors, the most striking and desirable being canary yellow, green, red, orange, blue and gold.  While all gembone has proven a solid investment in recent years, red, orange gembone combines with yellow cells with black cell walls has been increasing at the highest rate.  Five years ago the piece below would have cost in the 30.00 a pound, today it can run ten times that or more.  Bright canary yellow has always sold for a premium compared to other colors and it's usually the first to sell at the rock shows.  The finest gembone sells by the gram but affordable, beautiful specimens can still be found for less.  Colorful whole rounds, vertebras, and joints are choice pieces for specimen collectors.  However when these pieces are agatized and have large multi-colored cells they are far more valuable. 

Spiderweb bone is usually clear and has distinctly visible web-like patterns.  This is translucent and often beautiful.  Such jewelry bone always takes a fine polish.  Fortifications in bone are rare, desirable, and add significantly to the value.  Distinctly colored cells with bands of different colors within each cell are very rare. Look for as many colors as possible within individual cells as this is prettier then just colored gembone itself.  Try and find gembone with all fortified cells.  The greater the wow factor the better the piece.  Most gembone sold today is not investment quality. Always evaluate not only the entire affect of the piece, but also how many killer stones could be cut from each?  Sometimes you will find pieces that weigh a few pounds or more where only a 2 or 3 inch area is gorgeous.  Think about having a cab or cabs made from the prettiest part.  Remember gembone will nearly always have better cuts as each slice cuts deeper.  You may find your rarest treasure with a single cut in a rock saw. A geode may be unremarkable one cut and choice museum specimen after one more.  The same applies to gembone where one sees the potential within.  It is a good investment to take a chance on some of these because although you may buy some pieces of lower value, you will also get some of the best pieces in your collection.

The best gembone is very hard and chips like flint.  As bone is often fractured carefully inspect the broken areas to determine for possible windows inside clueing the buyer in on the interior.  Some fractures or weather cracks are normal in all investment grade pieces. The finest in the world is still 140 million years old and probably can be polished to hide any fractures so long as they are very thin.  Glass or porcelain-like specimens are excellent gembone.  The very hardest bone has the highest silicate content.  If you can examine the piece before buying tap a small piece of metal and listen for the bone to make a ping sound.  This will determine a high silicate content.  Most highly agatized pieces don't make this sound.  

Look under dino bone, dinosaur fossils, and gembone when searching for gembone.  Frequently the very best deals are listed in areas most didn't realize listed these pieces.  Also look for pieces of gembone sold under moss agates as some gembone is very hard to detect until cut into.  Look for jaspers as well as some bone became jasper during fossilization.  Look for opalized gembone as well.  Some is rainbow colored that is highly opalized and exhibits brilliant fire.  Some calcite will also be opalized although the agatized is more valuable.

Ask questions before you buy, get the dimensions, look for thin areas, and especially examine both sides?  Make your decision based on eye appeal or wow factor, consistency, size, answers to your questions and the big picture. Gembone that is dark, dull, or lacks definition is usually a poor choice.  Some black bone is very hard.  Gembone with black webbing with hidden vibrant colors is valuable and often undetectable.  All you will possibly see are a few colorful cells scattered around the entire surface against a black background. This may indicate a museum quality piece unknown to the seller.  Both desert varnish and a black shiny matrix can indicate high quality.  Remember it is worth buying pieces with potential as often the best part of the rock lies just a slice away.