large Tiger's Eye (Trancoso Coll.)

Item Description

At 2.5 kilos, this is a colorful, impressive sculptural large sliced and polished banded iron formation (BIF) slab from the Brockman Tiger eye mine of Western Australia. BIFs are distinctive units of metamorphosed sedimentary rock consisting of alternating layers of iron oxides and iron-poor chert (Wikipedia). BIF at this mine is Archaean-Paleoproterozoic Hamersley Group (about 2.5 Ba) (MINDAT). They are thought to record the Great Oxygenation event of the Earth's oceans. Banded iron formations account for more than 60% of global iron reserves (Wikipedia). "Golden Bands are the result of iron and sodium dissolving and leaving traces between crocidolite and quartz creating the golden color. Red streaks in the stone are Red Jasper between Hematite streaks." (Vasco Trancoso). The specimen is illustrated in the MINDAT Photo Gallery for the locale. Mass is 2537 grams or 5.6 pounds. Ex Dr. Vasco Trancoso Collection. He is a prominent Portugal collector and doctor near Lisbon. He collected for 60 years and built a fine worldwide display collection, that we recently purchased in Europe. A fine, colorful and sculptural large example from the locale.