Thin sections of the rocks of Krakatoa

Sections of Krakatoa lavas at x25, x35 and x250 magnifications. Krakatoa, the island in the Sunda Strait, Indonesia, erupted in catastrophic explosions on 27 August 1883. Figure 1. Older andesite at x25 magnification. Figure 2. Older andesite at x250 magnification showing microlites of feldspar, tridymote and magnetite. Figure 3. Crystal of feldspar at x35 magnification. Figure 4. Glassy base of porphyritic pitchstone at x250 magnification. Figure 5. Section of porphyritic obsidian at x25 magnification. Figure 6. Section of porphyritic obsidian at x250 magnification. Plate 3 from The eruption of Krakatoa, and subsequent phenomena. Report of the Krakatoa Committee of the Royal Society, edited by G.J.Symons (London, Trubner & Co., 1888). The plate is inscribed: ‘Krakatoa. Rep.Roy.Soc.Com. Plate 3. Sections of the Rocks of Krakatoa. A.E Tutton, del. Parker & Coward, lith. West, Newman & Co. imp.’