Sort of. Chiaroscuro isn't strictly black and white. You can use other values of grey. Here's an example by Giovanni Baglione:
http://en.wikipedia.org/wiki/Image:Baglione.jpg
While it is in color (I want you guys to focus more on value than color, hence why I want achromatic works this week), Baglione does use value extensively to produce the effect of depth in the painting. Notice how the top angel tends to pop out over everything else with the near white skin tone and the bottom angel tends to be behind it with the lesser values? That's how chiaroscuro works.
Also, I suppose the better way to define achromatic is to say colorless, since black and white tends to mean strictly those two colors. I'm going to fix that now... ^_^;