Silver Blue Topaz December Birthstone Necklace, Rose Slider - a rose that will stay fresh forever. Two delicate petals clasp a center gemstone, a pastel Light Blue Topaz birthstone measuring 4.5mm. Four more petals curl up and away from the central design. The chain passes through the design virtually unseen, giving the pendant a floating appearance. Fashioned with care in our Northern Michigan foundry, this piece comes with a sparkling 18" chain. Sterling silver.