The dark-appearing veins following fractures in the Gold Sheen sapphires appear to have formed after the exsolution of Fe-Ti oxides.
Those from Thailand, Australia and Laos are known to have inclusions caused by exsolution of hematite and ilmenite (Hughes, 1997, pp.
The fine-grained groundmass and minor granophyric (wormy) to more prevalent graphic (cuneiform) texture resulted from quench crystallization (low degrees of supercooling) of the dyke, possibly enhanced by vapour exsolution and depressurization (see Fenn 1986; Lentz and Fowler 1992).
Petrology of the Lake George granodiorite stock, New Brunswick: implications for crystallization conditions, volatile exsolution, and W-Mo-Au-Sb mineralization.
It is the expansion of the volatile phase following exsolution
and magmatic fragmentation which produces the kinetic energy required to accelerate the magma-volatile mixture to the surface producing an explosive eruption.
The miscibility gap is narrower at high temperatures, so that under slow cooling conditions, early formed augites and low-Ca pyroxenes develop exsolution
lamellae as low-Ca pyroxene and augite (respectively) are expelled from the structures.
Occurrence: The grains in Indarch probably formed by exsolution
of Si and N from kamacite, perryite and schreibersite during parent-body metamorphism.
In ore from Kipushi, needles and grains of gallite occur in sphalerite and in chalcopyrite as exsolution
Magnetite commonly exhibits an exsolution
texture comprised of intergrown magnetite, hematite, rutile and (rarely) translucent brown euxenite with a yellowish alteration surface.
Pyrrhotite occurs as coarse crystals with flame exsolutions
of pentlandite and surrounded by polycrystalline, chain-like pentlandite aggregates, yielding similar textures to those observed in Sudbury ores.
In fact, the Na plagioclases from the plagiogranites are cloudy and show K-feldspar exsolutions