Agate, which is
used to inlay the jewelry and carve the craftwork, is a kind of
precious stone. Agates in different grades in red, blue, purple
and pink colors, and with transparence, less impurity, less sand
inlay, less crack are all best, among which the complete block
weigh more than 4.5kgs is of top grade, more than 1.5kgs is of
the first, and between 0.5 and 1.5kgs is the second.