The key cation-sites M3 and A1 (and, in principle, M2) determine the root name. In both clinozoisite and allanite subgroups no prefix is added to the root name if M1 = Al. The prefixes ferri, mangani, chromo, and vanado indicate dominant Fe 3+ , Mn 3+ , Cr 3+ , and V 3+ on M1, respectively. In the dollaseite subgroup no prefix is added to the root name if M1 = Mg. Otherwise a proper prefix must be attached; the prefixes ferro and mangano indicate dominant Fe 2+ and Mn 2+ at M1, respectively. The dominant cation on A2 (other than Ca) is treated according to the Extended Levinson suffix designation. This simple nomenclature requires renaming of the following approved species: Niigataite (old) = clinozoisite-(Sr) (new), hancockite (old) = epidote-(Pb) (new), tweddillite (old) = manganipiemontite-(Sr) (new). Minor modifications are necessary for the following species: Strontiopiemontite (old) = piemontite-(Sr) (new), androsite-(La) (old) = manganiandrosite-(La) (new). Before a mineral name can be assigned, the proper subgroup has to be determined. The determination of a proper subgroup is made by the dominating valence at M3, M1, and A2 expressed as M 2+ and or M 3+ , not by a single, dominant ion (i.e., Fe 2+ , or Mg, or Al). In addition, the dominant valence on O4: X -or X 2-must be ascertained. The dominant trivalent cation on M3 determines the name, whereas the A2 cation appearing in the suffix has to be selected from among the divalent cations. (2) Allanite and dollaseite subgroups: For the sites involved in the charge compensation of a heterovalent substitution in A2 and O4 (i.e. M3 in the allanite subgroup; M3 and M1 in the dollaseite subgroup), identification of the relevant end-member formula must take into account the dominant divalent charge-compensating octahedral cation (M 2+ ) and not the dominant cation in these sites.Formal guidelines and examples are provided in order to determine a mineral "working name" from electron-microprobe analytical data.

Two pumpellyites with the general formula W 8 X 4 Y 8 Z 12 O 56-n (OH) n were studied using 57 Fe Mo¨ssbauer spectroscopic and X-ray Rietveld methods to investigate the relationship between the crystal chemical behavior of iron and structural change. The samples are ferrian pumpellyite-(Al) collected from Mitsu and Kouragahana, Shimane Peninsula, Japan. Rietveld refinements gave Fe(X):Fe(Y) ratios (%) of 41.5(4):58.5(4) for the Mitsu pumpellyite and 46(1):54(1) for the Kouragahana pumpellyite, where Fe(X) and Fe(Y) represent Fe content at the X and Y sites, respectively. The Mo¨ssbauer spectra consisted of two Fe 2+ and two Fe 3+ doublets for the Mitsu pumpellyite, and one Fe 2+ and two Fe 3+ doublets for the Kouragahana pumpellyite. In terms of the area ratios of the Mo¨ssbauer doublets and the Fe(X):Fe(Y) ratios determined by the Rietveld refinements, Fe 2+ (X):Fe 3+ (X): Fe 3+ (Y) ratios are determined to be 22:14:64 for the Mitsu pumpellyite and 27:8:65 for the Kouragahana pumpellyite. By applying the Fe 2+ :Fe 3+ -ratio determined by the Mo¨ssbauer analysis and the site occupancies of Fe at the X and Y sites given by the Rietveld method together with chemical analysis, the resulting formula of the Mitsu and Kouragahana pumpellyites are established as Ca 8 (Fe 0.88 2+ Mg 0.68 Fe 0.77 3+ Al 1.66 ) R3.99 (Al 5.67 Fe 2.34 3+ ) R8.01 Si 12 O 42.41 (OH) 13.59 and Ca 8 (Mg 1.24 Fe 0.65 2+ Fe 0.46 3+ Al 1.66 ) R4.01 (Al 6.71 Fe 1.29 3+ ) R8.00 Si 12 O 42.14 (OH) 13.86, respectively. Mean Y-O distances and volumes of the YO 6 octahedra increase with increasing mean ionic radii, i.e., the Fe 3+ fi Al substitution at the Y site. However, change of the sizes of XO 6 octahedra against the mean ionic radii at the X site is not distinct, and tends to depend on the volume change of the YO 6 octahedra.Thus, the geometrical change of the YO 6 octahedra with Fe 3+ fi Al substitution at the Y site is essential for the structural changes of pumpellyite. The expansion of the YO 6 octahedra by the ionic substitution of Fe 3+ for Al causes gradual change of the octahedra to more symmetrical and regular forms.

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Chromian epidote was found in pebbles of omphacite rock derived from the Sambagawa metamorphic rocks in central Shikoku, Japan. The pebbles consist of chromian epidote, omphacite, amphibole, muscovite, phlogopite, chromite, albite, and zircon. The chromian epidote crystals are dark yellow to brown. Microscopically, they are subhedral and are pleochroic from yellowish orange to pale yellow colorless. Chromian epidote has a zonal structure. Typically, cores of Sr rich epidote are overgrown with Ca epidote; alternatively Ca epidotes are rimmed by and/or intergrown with REE rich epidote. However, Cr distribution is not related to the zonal structure caused by Ca ↔ Sr and Ca + M 3+ ↔ REE 3+ + M 2+ substitution since regions of higher Cr concentration generally occur around chromite grains. The chromium content of epidote reaches 5.7 wt% Cr 2 O 3 (0.36 Cr apfu/12.5 oxygens). In contrast, the Fe 3+ content of the chromian epidote varies in a narrow range (5.1 to 8.9 wt% Fe 2 O 3 ) irrespective of the chromium content. Associated minerals surrounding chromite (omphacite, amphibole, muscovite, and phlogopite) also tend to have a high and variable chromium content caused by Al ↔ Cr substitution, but with a nearly constant Fe content in individual minerals. Chromite is considered to be the source material of the chromian epidote and the associated minerals. The heterogeneous distribution of chromium may be attributed to the immobility of chromium under metamorphic conditions. The maximum Cr content of the chromian epidote in the present study is less than that of Fe 3+ poor chromian epidote from other localities, whereas the Fe 3+ content is greater. The substitution of Cr 3+ for Al in the M3 site of the studied chromian epidote may be limited by the ferric iron occupying the M3 site to the extent of 0.52 apfu.