We collected Seokganju minerals (regions in Gyeryong Mountain, Sangsin-ri, Banpo-myeon, Gongju Chungcheongnam-province), which were used as natural color pigments for grayish-blue during the 15th~16th centuries of the Joseon era, and investigated their crystallographic features to develop a black pigment having a spinel structure. By a Raman analysis, the color of Seokganju under transparent glaze as a pigment for painting was black because hematite (Fe2O3) in Seokganju was converted to magnetite (Fe3O4) However, Seokganju into the transparent glaze as a pigment was brown because of hematite (Fe2O3) and small amounts of maghemite (γ-Fe2O3) in Seokganju minerals. Only Seokganju mineral is used, it is not suitable for black pigment into the transparent glaze. This study tried to develop a spinel crystal black pigment stabilized by Seokganju with CoO, Cr2O3, NiO, and MnO2 at 1280 oC. A Raman spectroscopy analysis was performed to verify the presence of Mn The results showed that it existed as spinel, and two crystal phases CoFe2O4 and MnFe2O4 were mixed. CoFe2O4 spinel has a dark grayish black color and Mn2O4 spinel has a greenish black color, and these two appeared as black. The color of a specimen calcined by adding 6 wt% of pigment mixed with 5 wt% of MnO2 added to lime glaze was analyzed with a UV spectrophotometer. When applying the color pigment, it appeared black stabilized with L*24.23, a* 0.12, b* .2.29 at 1260 oC oxidative calcination, With 1240 oC reduction firing, it is appeared black stabilized with low brightness of L* 23.13, a* .1.12, b* 0.54.