Janet Isherwood Jewellery 18ct white gold Tanzanite and diamond pendant Tanzanite 4.24ct Diamonds weight 0.05ct. JIN008 Price excluding chain. Janet Isherwood Jewellery pieces designed and manufactured in our own on-site workshop can be recreated in any precious metal with a choice of precious and semi-precious stones. Subject to material prices at time of order. For more details please ring the shop and speak to an experienced member of staff.