Found in cavities and fissures in unusual felsic igneous rocks, astrophyllite is associated with feldspar, mica, titanite, zircon, nepheline, and aegirine.
22.
Typical pumice contains crystals of biotite, hornblende, plagioclase, quartz, and sanidine, with minor amounts of apatite, iron oxides, and titanite.
23.
Other minerals common in minor amounts include sodium-rich pyroxene, biotite, titanite, iron oxides, apatite, fluorite, melanite garnet, and zircon.
24.
The mineralogy of the sill consists principally of plagioclase feldspar, several varieties of pyroxenes, and olivine, with minor biotite, titanite, zircon and oxides.
25.
It occurs in association with magnetite, sphalerite, chalcopyrite, skutterudite, allanite, zoisite, scapolite, titanite, calcite along with numerous other Co Ni sulfides and arsenides.
26.
Associate minerals include : microcline, nepheline, aegirine, lamprophyllite, lorenzenite, catapleiite, murmanite, arfvedsonite, sodalite, aenigmatite, rinkite, l�venite, titanite and titanian magnetite.
27.
Eclogite that is brought to shallow conditions is unstable, and retrograde metamorphism often occurs : secondary amphibole and plagioclase may form reaction rims on the primary pyroxene or garnet, and titanite may form rims about rutile.
28.
It occurs in nepheline syenites and pegmatites in association with aegirine, nepheline, microcline, arfvedsonite, elpidite, loparite, eudialyte, astrophyllite, mangan-neptunite, lavenite, rinkite, apatite, titanite and ilmenite.
29.
Peters showed us dozens of local minerals, including a transparent blue-green beryl found on 176th Street and Amsterdam Avenue and a very reflective, yellowish-green crystal called titanite discovered on 167th Street near the Harlem River.
30.
In some retrogressed eclogites and accompanying more silica-rich rocks, UHP ( ultrahigh-pressure ) metamorphism has been recognized only because of the preservation of coesite and / or diamond inclusions within trace minerals such as zircon and titanite.
