Abstract

• Man Sin is located about 5 km to the northeast of Mogok. It is bounded by Latitudes 22 57 05 to 2258 30 N and Longitudes 96 32 00 to 96 33 00 E, in part of UTM Map 47Q KF 2296- 09. Jedi spinel (Hot spinel) was first discovered at Man Sin mine in 2009. This mine produces as varieties of coloured spinel, but most of them are intense red spinel principally Jedi spinel (Hot spinel).Chemical analyses of Man Sin spinel indicate that Al2O3ranges from (71.5 – 60.5 wt ) and MgO from (26.6 – 18.5 wt ). The high concentrations of elements were Cr (3.66 – 0.008 ppm), V (0.633 – 0.005 ppm), Fe (2 – 0.03 ppm), Zn (0.725- 0.038) and Zr (1.103 – 0.219 ppm) respectively. Ti (0.113 – 0.008 ppm) and Ga (0.052 – 0.003 ppm) are generally low in concentration. FeTivsVCr and CrTivsVFe plots indicate that they are negatively associated. In Fe-V- Cr Ternary diagram, the red spinel from the Man Sin mine has two population: one is coloured by higher Cr content (> 80 ppm) and V content (> 40 ppm) but Fe content is (12 to < 10 ppm) in red spinel. The other group has average value of Cr and V ranging from (40-60 ppm). In these two groups, one which has higher Cr content shows more attractive red colour. Moreover, pink spinel also shows two groups. One is rich in Cr and other is rich in V. Fe concentration in these two groups is intermediate (35-55 ppm). One sample shows the significantly excessive Fe concentration (nearly 100 ppm) and thus the colour of this spinel is greenish blue. Trace elements (V, Ti and Zr) are positively associated with Cr but other trace elements such as Fe, Ga and Zn are negatively associated with Cr, which display increase of Cr content with decrease of Fe, Ga and Zn contents. Conversely, red spinel from Htayan Sho mine indicates that Fe content is (> 40 ppm) and the amount of V and Cr contents is (< 60 ppm). So, the constraint on the attractive colour of Man Sin Hot spinel is due to the Cr rather than other trace elements such as V and Fe; pink and purple spinel are due to Fe and Cr, V and Ti, and the green spinel is due to the Fe. On the other hand, red spinel from Htanyan Sho is due to the average concentration of Fe and V rather than Cr and the purple spinel is due to higher concentration of Fe than V respectively.