This is a nice sized garnierite heart, a big handful! It is roughly 4 3/4" across and about an inch thick. It is a wonderful olive-green color (it's hard to describe what that greenish-tan is), with a patch of lighter green visible on the side.
Garnierite is commonly referred to as Green Moonstone, but is actually a variety of Serpentine that has high nickel content. While the bright green is kind of neat, I actually prefer the softer olive -- it makes for a very calming, yet energizing heart chakra stone. This would be a perfect size to meditate with, resting it in both hands.
It weighs 600 g.