The term “Twinning Wisp” on a GIA diamond grading report indicates the presence of intergrowth within the diamond crystal. The clarity characteristic twinning wisp means that portions of the diamond crystal have twisted together within a twinning plane.
A formation of twinning wisps within a diamond usually contain a variety of inclusions, such as diamond crystals, feathers (minute fractures) and clouds of pinpoint size diamond crystals. The diamond crystals trapped within the twinning wisps may be light or dark in color.
At higher degrees of magnification, twinning wisps often look like white or black stripes. Twinning wisps might also look like streaks of cotton candy running throughout the diamond. Twinning wisps are not necessarily bad inclusions. They simply need to be carefully evaluated on a stone-by-stone basis to determine whether they affect visual performance.
The twinning wisps within this diamond are indicated on the plotting diagram featured on the GIA diamond grading report by the five red squiggly lines that extend outward from the center of the table facet towards the girdle edge of the diamond.
If you look closely at the clarity photographs provided of the diamond above, you should be able to see the twinning wisps located in the relative three o’clock and nine o’clock regions; just look for darker stripe-like patterns of diamond crystals.
Note that just because inclusions may appear dark in a clarity photograph does not necessarily mean that they are actually dark in appearance because the light source located behind the diamond can make light inclusions look dark.
They say that a picture is worth a thousand words, right? With that in mind, focus your attention on the plotting diagram for this 1.198 carat, G-color, SI-1 clarity, James Allen True Hearts diamond. The squiggly red lines that you see traipsing across the middle of the plotting diagram are the twinning wisps.
Yes, those red lines, right there in the middle of the table facet which extends outwards towards the edges in the relative five and nine o’clock positions.
But, that’s not all… Oh no, there are a few more visible within the crown facets. There is also a twinning wisp hidden under the upper girdle facet in the two o’clock position. And another twinning wisp under the kite-shaped bezel facet in the four o’clock position.
And there is another twinning wisp which crosses under the facet line for the bezel and upper girdle facets in the nine o’clock region. In fact, the only inclusion within this diamond which is not a twinning wisp is the diamond crystal under the upper girdle facet in the 10 o’clock region.
All of which might lead you to believe that this James Allen True Hearts diamond is heavily laden with twinning wisps, which I suppose it is from one perspective. The question is whether all of those twinning wisps are having a visual impact or not?
Knowing what twinning wisps look like will make it easier for you to see them. Here is a screenshot of the 1.198 carat, G-color, SI-1 clarity, James Allen True Hearts diamond. The red arrows which I added to the image on the right identifies the twinning wisps within this diamond:
The twinning wisps within this diamond are rather ghost-like and are not that easy to see. While the twinning wisps within other diamonds might be more visible, especially if the diamond crystals trapped within the twisted crystal planes are darker in color.
Inclusions within diamonds can be light or dark in color and tone. Diamond inclusions such as diamond crystals and twinning wisps can often appear dark in a clarity photograph when they appear light or translucent when being viewed through a 10x diamond grading loupe.
The inclusions within diamonds can appear darker in diamond clarity photographs because they are being backlit so that the location and extent of the inclusions can be identified, this is a lot like taking a photograph of somebody with the sun setting behind them; the subject of the photograph will appear dark unless a flash is used to provide a light source from the other side… the problem is that this usually makes it difficult to see the inclusions within the diamond, because of all the sparkle that it creates.
It can be difficult to ascertain whether the inclusions within a diamond are light or dark in appearance. Thus, I generally only consider diamonds that contain twinning wisps if they are being offered diamond dealers who carry physical inventory. All it takes is a phone call to get them to walk over to the vault, pull the diamond and take a real good look at it for me.
This 1.092 carat, E-color, SI-1 clarity, Brian Gavin Signature diamond contains twinning wisps. This is a good example of the type of diamond with twinning wisps that I would buy and/or recommend. If you look at the clarity photograph to the left, you will see that the twinning wisps are minimal and difficult to see.
Click on the link above to see the diamond grading report and you will see that the twinning wisps are not very extensive on the plotting diagram featured on the diamond grading report.
Long story short, this is an SI-1 clarity diamond at the higher end of the spectrum. Thus, it’s a great example of the type of SI-1 clarity diamond with twinning wisps that I would buy myself.
Keep in mind that each diamond clarity grade represents a range or spectrum of inclusion. Which means that some SI-1 clarity diamonds are going to look better or worse than others. Some SI-1 clarity diamonds will be on the higher end of the spectrum towards VS-2 clarity. While other SI-1 clarity diamonds will be on the low end of the spectrum towards SI-2 clarity. And other SI-1 clarity diamonds will be right in the middle of the range and are what we refer to as a textbook SI-1 clarity diamond. The same principle applies to twinning wisps within diamonds, some will be more extensive and visible than others.
Be sure to take the video for this 1.092 carat, E-color, SI-1 clarity, Brian Gavin Signature diamond for a spin. Click down the left button of your mouse over the video frame and hold it down while you drag the diamond left or right.
Twinning wisps within diamonds vary from stone to stone and the visibility will differ depending on the depth and location within the diamond. Thus, I find it helpful to have video of the diamond, so that I can examine the extent of the inclusions from facet-to-facet.
I also like being able to examine a diamond with twinning wisps under different light sources. One of the reasons why I like Brian Gavin Diamonds is because they provide video of the diamonds as seen under several different lighting types.
The initial video shows the diamond under normal diffused lighting. While the brilliance video shows the diamond under a brighter light source which enhances the brilliance of the diamond. The sparkle video is my favorite because it shows how the diamond is going to dance and sparkle under brighter light sources.
One thing to keep in mind when viewing the sparkle video is that the speckled platform that the diamond is sitting upon tends to reflect up into the diamond and can make it seem more included when in fact you’re only seeing reflections of the platform reflecting throughout the diamond. The sparkle factor of the diamond is so spectacular that it reflects everything around it including the speckled platform which sits beneath it.
My personal preference for diamonds that contain twinning wisps as an inclusion type is that they be more transparent in appearance. Larger formations of twinning wisps that contain diamond crystals that are dark in appearance might be easier to see without magnification. It’s also worth mentioning that larger clusters of twinning wisps might affect the visual performance of the diamond. I’ve seen instances where twinning wisps within diamonds make the diamond appear to be cloudy or milky. While there have been other times when the twinning wisps have been of no consequence and not had any effect on the visual properties of the diamond.
In my experience, the presence of twinning wisps that contain diamond crystals that are primarily translucent, do not affect the visual performance of the diamond. In which case, I would not reject a diamond solely on the basis that it contains twinning wisps. In fact, I’ve already stated that I would buy the 1.092 carat, E-color, SI-1 clarity, Brian Gavin Signature diamond above. The twinning wisps within that SI-1 clarity diamond are smaller in nature and appear to be of no consequence.
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