Serpentine 蛇紋石

As part of the natural geological formations series, or “rocks and stones“, here is a pretty green and white slab, a type of jade that might be called Serpentine. The naming probably comes from the observed line or squiggly type structures (green) that form in the material (overall material is white colored), such as can be seen in the optical image.

Loading the sample into a scanning electron microscope (SEM) for imaging and elemental analysis.

Scanning electron microscope images of the sample is shown in the next image. Notice the texture of the surface showing the underlying crystal structure. The material is similar in elemental analysis with quartz, a form of silicon oxide SiO2, as verified from the energy dispersive x-ray (EDX) measurements.

SEM image of the rock surface in (a). The EDX spectrum in (b).

The ratio of Silicon:Oxygen is measured as 33.3%:66.7%. Interestingly, in this measurement, other element types are not detected at the or near the surface of the slab. That means the color variation of the material, the white and green color, is likely coming from structure variations or the way light is bouncing around interfaces inside the crystal or near the surface.