Positively regal and exceptionally radiant, our pendant necklace provides unmatched elegance. An ethereal 5.50 carat pear-shaped sky blue topaz gem is framed by .20 ct. t.w. white and blue diamonds in 18kt yellow gold over sterling silver. Party-ready and also perfect for a date night! Black rhodium. Box chain. Springring clasp, diamond and sky blue topaz pendant necklace. Our blue diamonds are natural diamonds that have been treated which causes the color change and then heated to hold the color. The color change process is permanent.