The Daith (Crux of Helix) is the fold of cartilage that sits beneath the rook and is closest to the ear canal.
Again, there must be enough cartilage to comfortably hold the chosen jewellery. Micro jewellery (1mm to 1.2mm gauge) often rests well in most Diath piercings because the Diath can be quite shallow, and again the diameter of the ball closure ring can be as little as a couple of millimetres larger than the thickness of the pierced cartilage.
Curved barbells are a better choice, over straight barbells and labrets.
Healing Time: 8 - 16 weeks
Ear cartilage piercings generally take longer to heal than lobe piercings.
This is often due to a combination of things, such as the location of the piercing in the cartilage, the type of jewellery used and the tension that jewellery creates to the structure of the cartilage.
Using biocompatible plastics (like PTFE), cleaning cartilage regularly, and increasing your intake of minerals will certainly benefit your piercing; however a piercing will almost always be doomed to failure if improper jewellery and poor planning are used and left unmonitored.