The sacred cup used at Mass is extraordinary because of the heavenly mystery it holds.
Christopher Carstens explains in his book Mystical Body, Mystical Voice: Encountering Christ in the Words of the Mass how the Mass is more a heavenly banquet than a re-enactment of an ordinary Passover meal.
Does it matter that Christ may not have used a “precious chalice” at the Last Supper? That he used a chalice is imperative for the Church and her re-presentation of his sacrifice; and while it may be that the chalice was not outwardly precious, it was made precious by its contents. For while the Mass and its Eucharistic prayer hearken back to actions of Christ in the upper room some two thousand years ago, that historical action currently exists in heavenly splendor, which is why it can be made present to us at all. The cup of the first Paschal meal in time is now furnished with divine splendors and is “the chalice of great joy, of the true feast, for which we all long,” and it is this divine chalice that our sacramental chalice emulates.
The Mass is viewed in Catholic theology as the “wedding feast of the Lamb” found in the book of Revelation. It is meant to remind us of and draw us toward our heavenly home and the place where we will encounter the Bridegroom in all of his glory.
Even more so, the Mass it not simply a reminder of heaven, it is where “heaven and earth kiss.” The sacrifice of the Mass brings us into contact with the divine and literally raises us up into heaven.
The Eucharistic Banquet is no ordinary meal.
For this spiritual reason, as well as for practical purposes, the bishops of the United States have put forth the following regulation regarding the material of the “precious chalice”:
328. Sacred vessels should be made from precious metal. If they are made from metal that rusts or from a metal less precious than gold, they should generally be gilded on the inside.
329. In the Dioceses of the United States of America, sacred vessels may also be made from other solid materials which in the common estimation in each region are considered precious or noble, for example, ebony or other harder woods, provided that such materials are suitable for sacred use. In this case, preference is always to be given to materials that do not easily break or deteriorate. This applies to all vessels that are intended to hold the Hosts, such as the paten, the ciborium, the pyx, the monstrance, and others of this kind.
330. As regards chalices and other vessels that are intended to serve as receptacles for the Blood of the Lord, they are to have a bowl of material that does not absorb liquids. The base, on the other hand, may be made of other solid and worthy materials.
332. As regards the form of the sacred vessels, it is for the artist to fashion them in a manner that is more particularly in keeping with the customs of each region, provided the individual vessels are suitable for their intended liturgical use and are clearly distinguishable from vessels intended for everyday use.
So Indiana Jones may have been correct to choose the “cup of the carpenter,” but the Mass we celebrate is much more than a meal with a carpenter and his close friends. It is the place where we come to the table of the Lord to be fed a “heavenly manna” that is called the “bread of angels.”