Natural Ametrine Identification: Understanding Color Zoning

Question
Hello, I recently bought a ring off the internet and it was advertised as an ametrine, 5 carats in weight and is emerald cut.  When I received the ring, the ametrine is exactly cut 50/50 with a light purple and a light yellow.  The question I have is this.  The line of demarcation between the two colors is a very straight line, no blending.  It looks very artificial.  Is it possible to have a natural ametrine with such a straight line separating the 2 colors and how can you tell the difference between a natural occuring ametrine and a lab created one?  About how much is a 5 carat ametrine worth/cost anyway?  Thank you for your time.

Answer
Hello Hippie Chick,

Ametrine can be exactly 50/50, the gemstone cutter can make that by how he orients the rough.  Ametrine is not very expensive so the odds of it being synthetic is low.
To find out for sure you would need to consult a gemologist.  He could test it.  But the stone is really not worth the cost.  You could buy a 5 carat stone for 20.00 on up.  Depending who you bought it from and the quality.  How the clean the stone is and how vivid the colors and how well it is cut.