What is ‘play of color’? Is it unique to opal? How can we tell?
This week, Justin dives into what play of color is in different gemstones and why the play of color found in opal is so special.
Most gem stones have a trace element in them that gives the gemstone its color and when faceted, light refracts around the facets to show off that gorgeous color. This is an awesome display but it’s not considered play of color – very few gemstones have this!
The technical explanation of play of color is the phenomenon of spectral colors created due to the orderly array of silica spheres in opal structure. In less technical terms (for those of us who like it straight forward), play of color in opal is caused by light reflecting off of silica spheres that are stacked neatly on top of each other. The size of these silica spheres determine what color the opal will be; reds, greens, deep blues – it’s the size that matters!
When the silica spheres are not neatly stacked together is when we see potch opal created; an opal that has matte color with no play of color. Not all opals have play of color; Mexican fire opal, for example, generally has no play of color unless it is gem quality. Only when you get play of color is a gem considered precious and that’s what makes opals, like ours, so rare.
To add to the difficult craft of valuing opal, it can sometimes look like an opal has play of color in certain areas that’s really just the reflection of light. This happens in crystal opals that are polished on both sides – the light shining on the opal is reflected through the gem, creating sparkles that are actually just reflections of that light. These opals still exhibit play of color but this is a side note when it comes to valuing the gemstone.
So what’s the difference in play of color of opal vs other gemstones?
Opals have 3 dimensional color play making it seem like you can look right into the stone whereas other gemstones appear 2 dimensional. This 3D color play effect gives depth and beauty to the wonderful gemstone that opal is and adds to its breathtaking beauty.
The information given in this video and on this blogpost has been checked and deemed accurate by our Gemologist friend Tony Smallwood – Gemologists to the stars!