What coil to use.

An even better question is what detector and what frequency are you using. If it is a small gold stick pin ear ring you will need a high gain detector with a frequency around 19 kHz or higher and a small coil. Something like a Nokta Makro Multi Kruzer, Anfibio, Gold Kruzer, Racer 2, XP Deus, ORX, Minelab Equinox, Fisher F75, F19, Teknetics G2+ or T2......there are others too. Any detector with below average recovery speed and target separation running below 10 kHz may miss it.

Obvious answer is the smallest coil for whatever machine you have. It slows you down in sweeps but I've make out good when using a 4x6 Shooter coil on my old Whites V3i. Stick pin earrings especially. The V3i is very slow. This technology we have today...I have found those type target, using the factory coils. I would still advise a very small coil if I knew my treasure was tiny.