The Diamante is a 7 line poem in the shape of a diamond. The first and last lines have one word, with the middle line being the longest. Often the first word and the last word are opposites. This is a typical form:
Line 1: 1 word - the theme
Line2: 2 adjectives about line 1
Line 3: 3 verbs about line 1
Line 4: 2 nouns about line 1, 2 nouns about line 7
Line 5: 3 verbs about line 7
Line 6: 2 adjectives about line 7
Line 7: opposite theme
Cinquain can mean any 5 line verse. However it also describes a diamond form similar to the Diamante. But the rules for the Cinquain are less strict.