Its an idea.

Lets get to the point.

Euclid

This object is in the form of a small knife. From close examination the knife was made around 15-16 hundreds. The knife was found in the basement of a man hidden behind a brick in the wall. After finding the knife, the man later died within the next week. The knife when held gives the user a deep hidden murderious intentions towards others. (Lucky us the man didn't kill anyone after he found it.)
If the user doesn't kill within 3-7 days of having it. They start get into a depression state. If the state lasts more than 24 hours the user will commit suicide.
Do not look at the knife for more than 5 minutes. After that you will see it has true "beauty" and will try to grab it. The knifes material is unknown. But from what has been seen it seems to be either copper or perhaps iron. The knife, even though centuries old, seems to be in good condition .

Keep in a 2 by 2 feet container made of pure steel. No one should enter the room the container is kept in for they will start to see the "beauty" under the container and try to get it out. If such happens. Either lock up subject or eliminate for the subject will become very hostile. The effects do wear off after 48 hours of being 5-15 meters of the knife (depending of the murderous mentality the person has)