Blue diamonds are very rare, like the pink diamond that sells for one million US dollars per carat. “Blues” are much less costly, but are still much more expensive that white diamonds. They are one of the most rare and valuable gemstones in the world. Their color is derived from a trace amount of boron in the stone.
As time passes, the blue diamond undergoes an astonishing color metamorphosis; it becomes a deeper blue that makes it much more valuable. The bluer the stone, the older it is. The blue diamond is the only gemstone in the world that alters its color as it ages. Your great-grandmother’s dark blue diamond is enormously valuable. Owners rarely sell these older stones because of their value; you may be very lucky to find a dark blue diamond at an estate sale.
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