“The igneous breccias consist of fragments of various rock types,
including hornfels, nepheline syenite, gabbros and pyroxenites usually
cemented by fine-grained albite. The rock fragments tend to be angular in
shape, and vary in size from a few centimeters to nearly 1 meter across.
Elongated, irregular cavities 5 – 15cm in length occur in the albite in the
interstices between the fragments, and contain a unique suite of superbly
crystallized minerals”.*
Igneous breccia from MSH
© Quintin Wight
In some breccia zones the rock fragments exhibit partial melting and reaction rims, and appear more rounded as a result of having been partially digested by the rising magma. Cavities are less common, smaller, or non-existent in this type of breccia”.*
| Actinolite Aegirine Albite Analcime Anatase Ancylite-(Ce) Arsenopyrite Ashcroftine-(Y) Barite Bastnäsite-(Ce) Biotite Brookite Calcite Carbocernaite Catapleiite Cerussite Cordylite-(Ce) Donnayite-(Y) Elpidite Epididymite Eudialyte Eudidymite Ewaldite Fluorapatite |
Fluorapophyllite Fluorite Gaidonnayite Galena Ganophyllite Gismondine Gonnardite Harmotome Joaquinite-(Ce) Kainosite-(Y) Labuntsovite Lead Leucosphenite Lorenzenite Magnesio-hornblende Mangan-neptunite Microcline Millerite Molybdenite Monteregianite-(Y) Narsarsukite Natrolite Nenadkevichite Paranatrolite |
Parisite-(Ce) Pectolite Pyrite Pyrophanite Pyrrhotite Quartz Richterite Rutile Sodalite Sphalerite Steacyite Stillwellite-(Ce) Strontianite Synchysite-(Ce) Tadzhikite-(Ce) Tainiolite Thomsonite Titanite Vinogradovite Wulfenite Xenotime-(Y) Yofortierite Zircon |
* From Mineralogical Record Vol 21, Horváth L. and Gault R.A.