While in Valencia for the World Meeting of Families, Pope Benedict celebrated Mass using what many believe to be the Holy Grail, or the chalice of the Last Supper. Years ago, Pope John Paul II celebrated Mass using the same chalice. He was harshly criticized for kissing the chalice because many scholars do not believe the chalice is actually the Holy Grail. While we may never know for sure if the chalice is truly the vessel used by Jesus at the last supper, does it really matter? I don't think so.
I am dissapointed when I hear people say that the Holy Grail has magical powers or the like. It like all other relics does not have magical powers. The person who posseses the Holy Grail does not gain any special power or authority and any person who would claim it does is sadly mistaken. Power and authority belongs to God alone and he grants his gifts upon people according to his will. These gifts are not for sale, nor can they be transferred from one person to another. Any benefit gained from the use of a relic is gained from God through the prayer and intercession of the communion of saints. Unfortunately there are still people like Simon Magus who think they can use God for their own gain. Like Simon Magus they will learn that God cannot be tricked.
We venerate relics because they are the closest we can come to the holy people and sacred events in the Church's history. I have never been a person who put much stock into relics, but when I was in Rome I discovered a different aspect of faith. We visited the Shrine of the Holy Stairs and I was as skeptical as one could be. I did not climb to the top by the stairs, nor did I do it on my knees. Rather, I went up the side stairs. Before I left I felt a strong need to touch the stairs. It was illogical and went against everything I believed about relics...unless it could be truly proven to be authentic, it meant nothing. And I mean proven without a doubt. As we were leaving the Shrine I turned and went back to the stairs, I placed my hand into the opening of the wood which encases the stairs and touched the stone step. I thought I would cry right then and there. Suddenly it didn't matter if there were really the stairs Jesus climbed, it was what they represented that mattered. Don't get me wrong, I still think proving the authenticity of relics is vital, but if it can't be proven it doesn't make the relic less important. I walked out of that shrine a different person, I left as a person who had a fuller understanding of faith. Faith is believing even when it can't be proven and knowing proof isn't everything. Credo, I believe.
Learn more about the Holy Chalice of Valencia here.
Postscript: I have a need to add this comment. We must be careful to remember that even the most sacred relics like the True Cross are nothing compared to the Real Presence in the Eucharist. Remember that although we the Eucharist is the Body, Blood, Soul and Divinity of Jesus Christ under the appearance of bread and wine any scientific tests would only show bread and wine.