Mishnat Hashavua’: Me’ilah 5:1

Is it a crime if you cause no damage?

If one makes even a prutah (i.e., a cent’s) worth of profit from sanctified property, even if he does not diminish its value, he is guilty of ma’al (misappropriation), according to Rabbi Akiva. But the Sages say, if it is a type of property that could be diminished, he is not guilty of misappropriation until it is diminished. But for any type of property that is not diminished [in value by being used], he is guilty of ma’al the moment he benefits. How so? If [a woman] put a [consecrated] necklace on her neck or a ring on her finger, or drank from a golden goblet, once she benefited [from the use] it is ma’al [even though the value is not diminished by her use]. But if [a man] wore a [consecrated] cloak, or garment, or chopped with a [consecrated] ax, it is not ma’al until the item was diminished [from the use]. If he plucked [wool] from a purification offering that was alive, it is not ma’al unless he diminished its value. If it were already dead, any benefit would be ma’al.

Comments 

Ancient societies considered Temple property to be strictly off-limits for personal use. In Jewish law, even an unintentional transgression required the person to restore the property with a 20 percent penalty and to bring an asham (sin) offering. What if he or she did no harm? This mishnah makes an interesting distinction—only if normal use would cause damage does it matter if in fact such damage occurred.

Question

How would you estimate the value of “borrowing” jewelry belonging to the Temple?