Step 1:
The backside of this paper is white.
Fold in half.

Step 8:
Fold the edge upwards.

Step 6:
Press these two parts against each other.

Step 10:
Glue both halfs together.

Step 9:
Repeat steps 6 to 8 on the right, see arrow

Step 5:
Turn the model.

Step 7:
Fold over this line.

Step 3:
Prefold over these four lines.

Step 2:
Prefold in half.

Step 4:
Fold the edge inwards on these two places, the mountain-folds are prefolded.

Done!
You can use any paper color you like for making the gemstones.