• journal_title：American Mineralogist
• Contributor：Gregory R. Lumpkin ; Mark G. Blackford ; Michael Colella
• Publisher：Mineralogical Society of America
• Date：2013-01-01
• Format：text/html
• Language：en
• Identifier：10.2138/am.2013.4236
• journal_abbrev：American Mineralogist
• issn：0003-004X
• volume：98
• issue：1
• firstpage：275
• section：Actinides in Geology, Energy, and the Environment

Davidite (A_1−xM₂₁O₃₈) samples from five different geological localities contain approximately 0.2 to 9.5 wt% UO₂ (0.02 to 0.65 atoms per formula unit) and <0.1 to 1.3 wt% ThO₂ (<0.01 to 0.09 atoms per formula unit). Maximum amounts of other notable cations include 3.7 wt% V₂O₃, 4.1 wt% Cr₂O₃, 2.5 wt% Y₂O₃, 5.6 wt% La₂O₃, 6.0 wt% Ce₂O₃, 4.0 wt% MnO, 2.4 wt% ZnO, 2.7 wt% SrO, and 4.9 wt% PbO. As a result of the variation in age and Th-U content, the calculated α decay dose ranges from ~0.2 to 44 × 10¹⁶ α/mg (~0.06 to 14.5 dpa). For samples with ages of 275–295 Ma, the critical dose for amorphization based on electron diffraction is ~0.8 × 10¹⁶ α/mg. Natural davidite is commonly altered to rutile, ilmenite, titanite, and other minor phases.