Is there a difference between "Grecian" and "Greek"?

As far as I can tell, "Grecian" and "Greek" both mean "of or pertaining to Greece." Is there any difference at all between them?

In Modern English, Greek is the usual adjective meaning of or pertaining to Greece.

Grecian is an earlier construction, with an adjective-forming -an suffix (American, Norwegian, Virginian), which is now pretty much relegated to stylistic and fixed phrase duty. It's common in the following expressions, among others:

• Grecian Formula
• Grecian urn
• Grecian style or Grecian dress
• Grecian sandals

But there is no Grecian restaurant, Grecian wine, or Grecian language.

"Grecian" means "in a style used by the inhabitants of Greece," and so anyone could make, say, a Grecian urn. "Greek" means either an inhabitant of Greece, or from Greece, so a Greek urn must come from Greece.