Cottrills blocks

OUR STANDARDS

Excessive Fluorescence

Fluorescence is a natural phenomenon that makes the diamond glow when exposed to ultra violet light. It can enhance the colour on a "tinted" diamond making it appear whiter than it really is. On a "rare white" diamond excessive fluorescence may detract from the colour giving it a milky appearance.

We reject diamonds which we determine to have strong or very strong fluorescence.

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