3.3.1. QMA Results (Kimberlite)

#### Mode

Kimberlite from Letseng consists of so-called phenocrysts (21% olivine, 20% pyroxene) and nondifferentiable phase (59%). This nondifferentiable phase (NDP) consists mostly of an irregular mixture of serpentine, chlorite, pyroxene, olivine and ore minerals (Figure 13).

**Figure 13.** Kimberlite: (**a**) hand specimen, (**b**) microphotograph under transmitted light with lambda/4 plate.

#### Grain Size

The grain size differs between the phenocrysts. The olivine shows a mean grain size of 679 μm, the pyroxene a size of 324 μm, the phenocrysts having a mean grain size of 503 μm overall (Figure 14). The diameter distribution of the phenocrysts shows a scatter parameter of 0.334.

**Figure 14.** Mineral grain size distribution of phenocrysts (olivine and pyroxene).
