Sand is common for casting, but containers (crucibles[1]) for heating and holding molten metal are often ceramic (historically, clay) or at least lined with a r

Sand is common for casting, but containers (crucibles[1]) for heating and holding molten metal are often ceramic (historically, clay) or at least lined with a refractory[2] material. Refractory materials may include sand, but I don't think sand alone (even compressed, as when used for molds) is strong enough for a crucible. [1] https://en.wikipedia.org/wiki/Crucible https://en.wikipedia.org/wiki/Crucible [2] https://en.wikipedia.org/wiki/Refractory https://en.wikipedia.org/wiki/Refractory