A vessel contains oil (Density = \(0.8 \, \text{g/cm}^3\)) over mercury (density = \(13.6 \, \text{g/cm}^3\)). A homogeneous sphere floats with half of its volume immersed in mercury and the other half in oil. The density of the material of the sphere is \( x \, \text{g/cm}^3 \). The value of \(x\) is