I really doubt the cup that Christ had at the last supper would be ornate. I think that is a fake.
IMO it was probably a simple cup, because Christ was a simple Rabbi on earth, not an earthly king.
the ornate part was added later. only the top part (the stone cup) is what they think could be the Grail.
It's not a fake - it is indeed a very old chalice, but probably not the original one used at the Last Supper. However, there is some suggestion that it was used in Rome for the celebration of the Eucharist very early in the history of the Church, and then eventually ended up in Spain (which was a Roman territory) during a 3rd century persecution.
There is another chalice in Spain, known as the Holy Grail of Galicia, in the 9th century church at O Cebreiro, a steep and foggy mountain known for the bad weather at its summit. This chalice is famous for a miracle: during a storm, a devout peasant came, as usual, to attend mass. The lazy and faithless monk didn't want to be bothered and said to himself the equivalent of, "oh, here comes that stupid peasant again, out in the storm, just to see a piece of bread and some drops of wine." And then the bread and wine turned into the flesh and blood of Christ before the monk's very eyes. The chalice and paten (which are 12th century) are preserved and visible in a glass case in the church.
So in other words, there are various ways in which something can be a sacred chalice or Holy Grail, if not "the" Holy Grail.
A defensible position. As an alternative, though, may I remind that He did not celebrate the Passover in His own house ... rather, in the house of someone wealthy enough to have a fully furnished spare dining room, that could be loaned to an itinerant rabbi and His disciples. Hence, the cup in question might have been very rich and ornate.
The chalice has two parts: the ornate stem and base - which no one is claiming as dating back to Christ's time - and the stone cup to which the ornate stem and base are attached.
It is the simple stone cup which is under discussion.
Though one might still argue that the cup being made of a single piece of agate shows that it was a nicer-than-normal piece of stoneware.
Valencia's sacred chalice is made up of two parts. The polished stone vessel on top is supposed to be the cup of the Last Supper. It is made of dark brown agate and measures 6.5 inches tall and 3.5 inches wide. Archeologists say it dates back to the first century B.C. and is of eastern origin, from Antioch, Turkey, or Alexandria, Egypt.
The part of the chalice that the cup rests upon was made during the medieval period. The chalice's stem and handles are made of fine gold, and its alabaster base is decorated with pearls and other precious gems.
The part that is suggested Jesus used, IS very simple.