The author recently examined a large 3.05 ct Fancy Light gray diamond featuring dark crystals scattered throughout (see above). It had a clarity of I3, the lowest grade for gem-quality diamond, but demonstrated that low-clarity diamonds can sometimes be more intriguing than their higher-clarity cousins. Stones with numerous eye-visible crystal inclusions such as this are sometimes referred to in the trade as “salt and pepper” diamonds.
Numerous attempts to identify the dark crystals using Raman spectroscopy proved unsuccessful. X-ray fluorescence revealed high levels of iron, leading the author to conclude that they were likely metal sulfides rather than graphite. This presumption has not been confirmed with Raman spectroscopy.
The author recently examined a large 3.05 ct Fancy Light gray diamond featuring dark crystals scattered throughout (see above). It had a clarity of I3, the lowest grade for gem-quality diamond, but demonstrated that low-clarity diamonds can sometimes be more intriguing than their higher-clarity cousins. Stones with numerous eye-visible crystal inclusions such as this are sometimes referred to in the trade as “salt and pepper” diamonds.
Numerous attempts to identify the dark crystals using Raman spectroscopy proved unsuccessful. X-ray fluorescence revealed high levels of iron, leading the author to conclude that they were likely metal sulfides rather than graphite. This presumption has not been confirmed with Raman spectroscopy.
