30 pieces of silver
From Matthew 27:3 - 27:8 (King James Version of the New Testament of the Holy Bible):
Then Judas, who betrayed Him, seeing that He was condemned, repenting himself, brought back the thirty pieces of silver to the chief priests and elders, saying: "I have sinned in betraying innocent blood." But they said: "What is that to us? See thou to that." And casting down the pieces of silver in the temple, he departed, and went and hanged himself. And the chief priests took the silver pieces, and said: "It is not lawful to put them into the treasury, because it is the price of blood." And they took counsel, and bought with them the potter's field, to bury strangers in. Wherefor that field was called, the field of blood, unto this day.
The site referred to in these verses is traditionally known as Akeldama, in the Valley of Hinnom, outside the walls of the Old City of Jerusalem, which was a source of potters' clay. Today, atop that site sits the Monastery of Saint Onuphrius.
We were given the sincere honour of photographing portions of the Monastery and the burial chambers and passageways beneath it.