So, the C natural on the violin is sort of like the sad C, because when you first learn to play the violin, you usually learn to play C sharp, like this.
You have open A. First finger on A is B. And then you have C sharp, second finger. But, if you're then going to learn a C natural, that is one half-step below a C sharp and it's right next to the B. So, then you would play this. A. B, first finger. And then, here's your C natural, right next to the B. They're touching.
So, then you have a little bit of a sadder, minor feel. That's an introduction to the C natural on the violin.