THIRTY BODY TONE BUYING GUIDE POSTERS BY THE AUSTRALIAN OPAL ASSOCIATIONThe owner of Seda Opals, Paul Sedawie, is the current President of the Australian Opal Association. The association has produced this guide to inform and educate buyers about the darkness of opals which range from a N to N9scale.This base body tone chart is a valuable buying tool for purchasing opals on the internet. It allows you to gauge the colour darkness of a stone moreaccuratelyas some stones can be over enhanced inphotos. Most internet sellers provide an accurate body tone rating (N1 to N9) of their stock. With this tool you have a better grading system of stones being offered and can easily compare stones between sellers. PLEASE NOTE: The Base Body tone refers to the darkness or lightness of a stone. The only determing factor is the front of the stone. You should ignore the back of the stone and its brightness. ROUGH OPAL: The body tone chart can also be used for rough that has been faced or pre rubbed. This will provide an idea of the darkness of the rough but PLEASE BE AWARE: when you rub it down further the grading can change. For example, a piece of black rough can get darker as you polish the top down. THIS IS NOT A BRIGHTNESS CHART. It is possible to have two stones with similar brightness but different body tone ratings. Only those stones achieving a base colour of N1 to N4 are considered Black opal, attracting the additional value associated with this class of opal. This poster is printed on high gloss paper measuring 1 x 8inches and is ideal for framing.Len Cram the noted opal literature author created the art work for this poster.The poster includes someinteresting opal patterns.
Keep one and you can give the other one as a gift.