Blue Nuance in Lab Diamonds
Blue nuance is a tinge of blue color present in HPHT diamonds resulting from excess boron in the diamond after the growth process. Lab diamonds with a measurable amount of boron are considered Type IIb, not Type IIa.
On the left, a 3.05ct F VS1 Cushion grown via the HPHT method with noticeable blue nuance. On the right, a 3.01ct E VS2 radiant grown via the CVD method without blue nuance.
The Bottom Line:
Not all lab diamonds are created equal, even within the same 4Cs. This is why it is imperative that a lab diamond expert inspect your lab diamond before purchase. It is also why you should work with a retailer who will take back your lab diamond via a trade-in or resale program to ensure you are buying a quality stone.