Use this dictionary for such questions (U means Uncountable, C countable):
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chocolate
noun
1 [C or U]
a sweet, usually brown, food made from cacao seeds, that is usually sold in a block, or a small sweet made from this:
a bar of chocolate
chocolate biscuits/mousse
milk/dark/white chocolate
I took her a box of chocolates.
2
[C or U] UK ALSO FOR hot chocolate
3
[U ] a dark brown colour
http://dictionary.cambridge.org/define.asp?key=13289&dict=CALD
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As you can see, it can be both.