This photomicrograph illustrates much of the mineralogy of the Dunkheld Lava flow. The microcline formed early but was then unstable in the remaining melt. Thereafter the microcline was being resorbed but cooling was fast enough that the microcline was not totally resorbed. Then plagioclase crystallised with an acicular nature and the olivine was last to crystalise, filling the gaps between the plagioclase, and forming glomeroporphs. XPL