Ah, finally a "structure rock".
Here are the questions:
1. What is this rock?
2. What is missing from the little cubic holes?
3. Why does the rock have that rectangular-prism shape?
Hint for the online audience: the words "Merced Falls" are written on the rock, this wouldn't give anything away to the south african students but I had to tell you anyway.
Solution to Rock of the Week #4:
Thanks to Johann Diener for the interesting rock!
1. (1 pt) 2 minerals?
: 1 point given for either feldspar or pyroxene.
2. (1 pt) Rock type?
3. (1 pt) Locality:
: any komatiite locality acceptable, e.g. Barberton Belt.