Summary[
edit] Description: English: Rutile-rich sand from the Holocene of Australia. (sample is about 98% rutile) This is a concentrate sample derived from modern sand along the eastern coast of Queensland, Australia. It is, in essence, titanium ore. Click once or twice on the photo to zoom in - the black and dark red grains are rutile (TiO2, titanium oxide), an important titanium ore mineral. Concentrations of heavy, valuable minerals (for example, gold, diamond, cassiterite, etc.) in beach sands or river sediments are called placer deposits. In this case, good long shore currents have concentrated rutile along the coast of Queensland. Monazite and zircon also occur in these sands - by-product concentrates have been made of these minerals. Pure titanium oxide is translucent and is called titania - its good sparkle and adamantine luster made it a popular synthetic gemstone decades ago (e.g., www.flickr.com/photos/ptorraca/5265350812 ). In nature, iron (Fe) is often substituted into the rutile molecular structure, as well as tin (Sn), chromium (Cr), and vanadium (V). Due to its iron content, natural rutile is opaque and black-colored, but it is also translucent red to very dark red, depending on the amount of Fe. Rutile is 6 to 6.5 on the Mohs Hardness Scale. It forms tetragonal prisms, usually striated. Rutile often forms twins that look like bent crystals - "elbow twins". At high temperatures, rutile and quartz form a solid solution; with cooling, rutile separates and the quartz ends up enclosing rutile crystals ("rutilated quartz" - see www.flickr.com/photos/jsjgeology/34510806931 ). In granites and pegmatites, rutile is common as small grains. Locality: unrecorded site at or near Tin Can Bay, coastal-southeastern Queensland, eastern Australia Provenance: collected in 1969 from a titanium ore feed for the Timet Mill in Henderson, Nevada, USA ("Timet" = Titanium Metals Corporation of America); the raw ore was dredged along the Queensland coast by Queensland Titanium Limited and then concentrated, using spiral concentrators; ore was then transported to Long Beach, California and then to Henderson, Nevada Photo gallery of rutile & rutilated quartz: www.mindat.org/gallery.php?min=3486 and www.mindat.org/gallery.php?min=3485. Date: 8 December 2020, 14:35:38. Source:
https://www.flickr.com/photos/47445767@N05/50696373366/. Author: James St. John.