"The black rice"
Translation:Le riz noir
You have been waiting in vain. It has already been answered for you. The answer is in the post immediately above yours.
I will repeat that post from zero4384 to save you the trouble of looking through the posts to see if your query has already been answered.
"Noir" is masculine and "Noire" is feminine.
You are simply wrong when you write noire is masculine.
Not all adjectives follow the noun. Some common exceptions are adjectives for age, good/bad, and size - these go before the noun. Refer to http://french.about.com/od/grammar/a/adjectives_4.htm
Many adjectives precede the noun.
This includes almost all adjectives that relate to:
B.A.G.S. is the mnemonic device to help you remember.
There are exceptions, sometimes even with the same word, which occur in sufficient number to keep it interesting.
See the post from cph shown above.
Le = the - as in the black rice. I eat that black rice right there. Definite
Du = de le = of the - as in _I eat ..of the=some black rice. Not any particular rice, not all the rice but of the=some rice. Indefinite
It is perfectly correct to use du riz when you are speaking of some rice. But this sentence was concerned with the rice. Not just any rice but the rice. They are different sentences in English as well as in French.