"Around her neck was a thick silver chain, on which hung a dark red pendant the size of a baby's fist." - City of Bones
There's a long story to this necklace that Isabelle Lightwood wears and warns her of demonic activity but it might be a spoiler if you haven't read all books in the series...let's just say Magnus is involved.
18 x 13 mm Swarovski drop fancy stone
All Sterling silver.
Engraving in the back: "Amor verus numquam moritur" ~ true love never dies
Available to ship in 5-7 business days