Comparison of two diamonds. The diamond on the left appears cloudy, dull, milky and lifeless compared to the diamond on the right.
Milky, hazy and dull diamonds. Reasons for diamonds being dull and sleepy.
There are various reasons why your diamond appears foggy, dull or cloudy. It is very difficult for an expert to advise on this without seeing the diamond. Some cloudiness can be reversed, depending on the cause. Read on to gain a better understanding of why diamonds may appear milky. Such diamonds are often referred to as sleepy diamonds, lacking life and sparkle compared to other diamonds.
Cloudy diamonds and clarity characteristics
Some diamonds feature clarity characteristics so dispersed that no single inclusion can be seen. Instead, inclusions spread within the diamond similar to within a suspension, slowing the passage of light and making the diamond appear milky. These diamonds will almost always appear good-for-the-money, lacking the dazzle of higher clarity diamonds.
Diamond Fluorescence and cloudy diamonds
Some diamonds fluoresce under UV light. Reviewing your diamond certificate, fluorescence will typically appear with a description such as: nil, very slight, slight, medium, or strong. Diamonds graded with strong fluorescence may exhibit a milky appearance, especially in strong sunlight. These diamonds will glow when a UV light is placed over the diamond.
Is fluorescence in diamonds good or bad?
If you’re confused about whether fluorescence is good or bad in diamonds, there is a clear explanation.
When fluorescence is a bad thing (reduced value in a diamond)
Strong fluorescence in white diamonds sometimes results in a milky hue. This is often most apparent in sunlight. For this reason, strong fluorescence often relates to a much lower price for a certified stone.
When fluorescence is a good thing in diamonds (adds value to the stone)
Tinted diamonds appearing slightly yellow sometimes benefit from a lift in whiteness as a direct result of fluorescence. UV light reflected back from tinted diamonds results in a whiter appearance. As a result, diamonds appear whiter than their specified colour grade. This effect appears when viewing a diamond from above. In contrast, viewed from the side, the true colour of the diamond is revealed.
‘Smoked’ diamond – oxidation of a diamond’s surface
On close examination of the surface of a milky diamond, a film or oily surface might be visible across the diamond. This film can result in the diamond looking milky or foggy. This is most apparent when the diamond appears to have ‘changed’ from a clear diamond to a cloudy looking stone. The reason for this could be that the diamond has become ‘smoked’. This effect can happen when the surface oxidizes at high temperature. The only remedy for this will be re-polishing the surface of the diamond under the expertise of a diamond polisher.
It’s always best to un-set diamonds before melting down the setting. At very high temperatures, a diamond’s surface can be oxidised resulting in a dull coated appearance.
Final note on milky diamonds
Milky diamonds are frequently sold at a very competitive price compared to bright, clear diamonds. For this reason, we recommend talking to an expert before making your purchase. Part of our work involved photographing certified diamonds for clients as part of our diamond concierge service. We also provide microscopic imagery and 365-degree videos in many instances where clients cannot visit to inspect diamonds in person.