Copper Chromite Black
A previous description read, "Black Spinel is the most permanent of blacks and is a neutral black in masstone. Because of its pigment's crystalline shape, Black Spinel dries to a matte finish when no painting mediums are added.“ -Gamblin Oils. Gamblin also notes that this color remains more neutral in mixes where other black paints may tend to cool in mixes. A comparison of Gamblin black paints and more information can be found at https://gamblincolors.com/choosingblackoilpaint/