2 different recipes. Brands sell different pigment mixtures under this name, so they won't all look or mix alike. Compare the pigments below; the most common is PBr7 Natural Iron Oxide.
Who makes it
PBr7 Natural Iron Oxide2
- Blockx Extra-Fine Oil Colours No. 212147
- Maimeri Puro Oil Colours No. 490
PBk7 Carbon Black + PR176 Benzimidazolone Carmine + PY74 Arylide Yellow 5GX1
- Lukas 1862 Artists' Oil No. 0101
Sizes are the ones each line is sold in; marks a size only some colors come in. Check the store for a particular color.