Detect thoughts

Detect thoughts, also known as ESP, is a divination spell that allows one to "listen" to surface thoughts.

Effect
The amount of information revealed depends on how long the caster studies a particular area or subject. The spell can penetrate barriers, but 30cm (1ft) of stone, 2.5cm (1in) of common metal, a thin sheet of lead, or 1m (3ft) of wood or dirt blocks it.

The post sundering version of the spell also allowed the caster to detect the surface thoughts of a creature and "detect" where they are. This spell could be used for interrogation and also to probe deeper into the targets mind. The spell could not detect or read the mind of very unintelligent creatures or creatures that doesn't speak any language. The spell reached 30 feet, and lasted 1 minute but could not penetrate 3 ft (91 cm) of wood or dirt, 2 ft (60 cm) of stone, 2 in (5 cm) of regular metals, or a thin layer of lead.

Arcane focus
A copper piece.