• A lustrous, blackish-brown rare-earth mineral consisting primarily of cerium, erbium, titanium, uranium, and yttrium.
  • A brownish-black mineral with a submetallic luster, found in Norway, which contains the metals yttrium, niobium (columbium), titanium, uranium, and some others.
  • A brownish black mineral with a metallic luster, found in Norway. It contains niobium, titanium, yttrium, and uranium, with some other metals.
  • A dark brown lustrous <xref>mineral</xref> that is a mixed <xref>oxide</xref> of <xref>cerium</xref>, <xref>erbium</xref>, <xref>titanium</xref>, <xref>uranium</xref>, <xref>yttrium</xref> and other more common metals, with the <xref>chemical formula</xref> (<xref>Y</xref>,<xref>Ca</xref>,<xref>Ce</xref>,<xref>U</xref>,<xref>Th</xref>)(<xref>Nb</xref>,<xref>Ta</xref>,<xref>Ti</xref>)2<xref>O</xref>6.
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