Figure 2
From: Role of pyrite in formation of hydroxyl radicals in coal: possible implications for human health
Scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDAX) of the coal sample containing the most sulphur (NIST # 2685b). The top image A shows grains of carbonaceous material with a cluster of 'bright' crystals. Image B is shows the 'bright' crystals magnified and an EDAX spectrum focused on the crystals reveals the presence of iron and sulfur (C). An equivalent spectrum was recorded on a pyrite sample (not shown). An energy of 15 kV and a working distance of 8 mm were used for both A and B, 1500 × and 15000 × magnifications were used for A and B, respectively.