https://bereket-haileab.geology.sites.carleton.edu/files/original/4c9268402ac35d0d6931fffdf8248f85.jpg ffd9caa64763cb8b922585d0e2ea0707 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Igneous Rocks Subject The topic of the resource This collection covers both volcanic and intrusive rocks, including rhyolites, granites, diorites, andesites, basalts, gabbros, diabases, pumices, obsidians, syenites, phonolites, peridotites, carbonatites, dacites, trachyte, dunites, xenoliths, ignimbrites, and pegmatites. Creator An entity primarily responsible for making the resource Bereket Haileab Source A related resource from which the described resource is derived Housed in Anderson Hall, Carleton College. Format The file format, physical medium, or dimensions of the resource Thin sections, thin section scans, hand samples, hand sample images, photomicrographs, chemical analyses (major elements, trace elements and REE analyses for selected samples). Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource BH250-208d Subject The topic of the resource Perovskite Mineral (Lava flow from Uganda) Description An account of the resource Major Minerals: perovskite (very large) Minot Minerals: phlogopite, clinopyroxene, muscovite, oxide (ilmenite) Optics: pseudo isotropic perovskite, grid-like or tartan plaid-like patterns Phase Transitions and Symmetry: Perovskite crystallizes in a high-symmetry cubic form at high temperatures but can undergo symmetry reduction upon cooling, transitioning to orthorhombic or monoclinic structures. This transition often results in pseudo-isotropic behavior and the appearance of grid-like or tartan-style twinning patterns under crossed polarizers. About the mineral Perovskite: Perovskite is an isotropic mineral with major significance across multiple disciplines geology, materials science, and solid-state chemistry. Chemical and Structural Characteristics: Chemical Formula: CaTiO₃ (calcium titanate) Crystal System: Cubic at high temperatures, but it commonly transforms to orthorhombic as the host lava cools. During this transformation, it retains a pseudo-isotropic appearance in thin section showing twining like features as it is seen in the photomicrographs and thin sections of BH250-208d. Being silica-poor, perovskite reacts with silica (SiO₂) to form sphene (titanite): CaTiO₃ + SiO₂ → CaTiSiO₅ Sphene (titanite) This reaction highlights its petrological behavior and links it to sphene (titanite), a mineral with similar optical properties. The similarities between the two are especially noticeable in thin section under polarized light. Geological Occurrence and Significance: For geologists, perovskite is an important accessory mineral found in, mafic and ultramafic rocks, Kimberlites and carbonatites and Mantle-derived xenoliths. Its high-pressure polymorph, is the most abundant mineral in Earth’s lower mantle, accounting for a significant portion of the planet's volume. This makes perovskite a cornerstone mineral in deep Earth research. Why should geology students care about Perovskite: Understanding perovskite is critical for grasping the structure and evolution of Earth’s interior, Its presence helps interpret seismic data and mantle composition. It can incorporate uranium while excluding lead, making it useful for U–Pb geochronology, especially in kimberlites. It hosts rare earth elements (REEs), niobium, and titanium critical elements in green energy technologies such as wind turbines, electric vehicles, and solar panels Optical and Physical Properties of Perovskite:  Brown, black, or reddish-brown in color and optically typically isotropic in cubic form, but may show weak anisotropy when preserved in orthorhombic symmetry making it pseudo -isotropic showing grid twining. In materials science and physics, synthetic perovskites are transforming solar cell technology. Perovskite is not just a mineral it is a structural archetype with deep relevance to both natural Earth processes and technological innovation. Whether it’s used to probe the deep mantle, date ancient rocks, or power future energy systems, perovskite sits at the intersection of geology, chemistry, and materials science. For future geologists, understanding perovskite means understanding how materials behave under extreme pressure and temperature, how elements cycle through the planet, and how science connects across disciplines to solve both ancient and modern challenges. Coverage The spatial or temporal topic of the resource, the spatial applicability of the resource, or the jurisdiction under which the resource is relevant Uganda Creator An entity primarily responsible for making the resource Bereket Haileab Source A related resource from which the described resource is derived From the rock collection of Bereket Haileab. Sample BH250-208d. Housed at Carleton College in Minnesota Contributor An entity responsible for making contributions to the resource Bereket Haileab Frank H. Brown Relation A related resource <iframe width="100%" height="480" src="https://drive.google.com/file/d/16vmgoh-LOnktydRQ-2UphPV7TY0KGadB/preview" allow="autoplay"></iframe><iframe width="100%" height="480" src="https://drive.google.com/file/d/1vtrvP-W7sQIR74beF4OhBxRXGrGZHuO7/preview" allow="autoplay"></iframe><iframe width="100%" height="480" src="https://drive.google.com/file/d/1nB5qcN7NKN7IsJ3D8GaLA4AMpCdXSKgy/preview" allow="autoplay"></iframe> 2.4 refractive index accessory minerals: Alkaline magmatism alkaline volcanic rock Clinopyroxene East African Rift euhedral perovskite fine-grained groundmass grid twining grid-like twinning high birefringence High refractive index mineral high relief igneous Ilmenite isotropic mineral (perovskite in XPL) mafic mafic volcanic rock mantle-derived magma massive perovskite crystals Orthopyroxene Oxide minerals Perovskite perovskite highest relief minerals porphyritic texture pseudo isotropic mineral pseudo isotropic perovskite REE-bearing phases tartan plaid-like patterns tartarn twining Ti-rich mineral assemblage titanium-rich phases twinned crystals twinned perovskite Uganda Ultramafic Volcanic Rock