Mystery Food!

Here is some Thursday randomness for you. Let's play a guessing game because it'll be more fun than me throwing some information at you about some random food. (It's not fun if there are not any guesses.)

I originated in India and have been cultivated for at least 3,000 years. According to a botanist I am a fruit, but according to a chef, I am a vegetable. I come in a variety of sizes and am best eaten raw. I am seasonally best in summer, but can be enjoyed all year. I contain an abundant amount of minerals but only in trace amounts because I am about 90% water. 

What am I?