The House of Tibara, Opal Specialists

What follows is the primary factors in determining the value of rough opal... but there's a lot more to this than meets the eye! We've also included a text file that you can download and take with you to the next gem show you attend. This will explain a lot of terminology and help you understand why certain properties are valuable and others are not.

Click here to download the Opal Buying Guide

FACTOR	DESCRIPTION	VALUE
Base Color and Degree of Translucence	White or Jelly (opaque) Grey Semi-black Near Clear Crystal Black Black (jet)
Fire Color	Green Blue Blue-Green Red-Green Multicolor (3, 4, or 5 colors) Red predominant, multicolor Magenta and True Purple (very rare)
Fire Pattern	Sunflash Pinfire Broad flashes Rolling flashes Harlequin (hard angled fire pattern visible from all angles) Broad rolling flashes
Fire Intensity	Very directional with dead areas Low intensity No directionality (shows fire from all angles) High intensity

FACTOR	LEAST VALUABLE	MOST VALUABLE
Quality of fire band in rough	Thin (triplets, dome cabs)	Thick (high domed or flat stones)
Penetration	Partial penetration of fire band	Penetration to whole outside periphery
Waste	Little fire in relation to waste - spare fire, large waste	More fire, less to little waste
Straightness	Fire band not straight or poor shape of rough relative to band	Fire band or bands straight
Intensity	Fire intensity muted or not bright	Brilliant intensity

NOTE: This grading method is an attempt to idealize a continuum of multiple characteristics, which vary somewhat independently. I hope this guide is helpful in your future purchases, or in assessing what you already have. The above conforms with the American Opal Society standards.