The term ‘alabaster’ may have been applied to travertine marble from Egypt or even softer gypsum but in the case of expensive items like perfume the better alabaster from stalagmites was probably used.
In any event there is no way of knowing what material the cup at the Last Supper was made from but being that it used what was present at the passover meal using a costly item like an alabaster vessel seems unlikely.
Gold? Even less likely for the unpretentious disciples.
Yes, I too have seen the mindless nonsense about a Holy Grail and such.
“Yes, I too have seen the mindless nonsense about a Holy Grail and such.”
Some groups such as the FreeMasons would take issue with that statement.
Not to mention the graven images.