2 different recipes. Brands sell different pigment mixtures under this name, so they won't all look or mix alike. Compare the pigments below.
Who makes it
PBr7 Natural Iron Oxide + PR101 Red Iron Oxide1
- Grumbacher Pre-Tested Artists' Oil No. P016
PBr7 Natural Iron Oxide1
- Blockx Extra-Fine Oil Colours No. 212143
Sizes are the ones each line is sold in; marks a size only some colors come in. Check the store for a particular color.