Diamond necklaces are necklaces that players can make by using a gold bar on a furnace with a diamond and a necklace mould. This requires a Crafting level of 56, and provides 90 experience when made.
A player enchanting a diamond necklace
Members can change a diamond necklace into a phoenix necklace by casting Enchant Level 4 Jewellery. This requires level 57 Magic, and grants 67 experience.
Grum's Gold Exchange in Port Sarim used to buy at a better price than High Alchemy, depending on his current stock. This has been adjusted to 50% of the High Alchemy value.
At 99 Divination, a player can create a Sign of the porter VI with a diamond necklace and 80 incandescent energy.