Giant Mumbai Diamond

The Giant Mumbai Diamond is a large (giant), precious diamond in the museum that was stolen by Sarah's sister, Anthea. The Giant Mumbai Diamond was then later hidden in a carrot cake but Samantha worked out where the diamond was and told Sarah, who then found the diamond in the cake. The diamond has not been mentioned since, appearing only in the fourth book. The diamond is very valuable and beautiful, as even police were on the case of the diamond's theft.