Two new monoclinic (P2 1 /m) epidote supergroup minerals manganiakasakaite-(La) and ferriakasakaite-(Ce) were found in the small Mn ore deposit of Monte Maniglia, Bellino, Varaita Valley, Cuneo Province, Piedmont, Italy. Manganiakasakaite-(La) occurs as subhedral grains embedded in pyroxmangite. Its empirical formula is A(1) (Ca 0.62 Mn 2+ 0.38 ) A(2) (La 0.52 Nd 0.08 Pr 0.07 Ce 0.07 Y 0.01 Ca 0.25 ) M(1) (Mn 3+ 0.52 Fe 3+ 0.28 Al 0.18 V 3+ 0.01 ) M(2) Al 1.00 M(3) (Mn 2+ 0.60 Mn 3+ 0.27 Mg 0.13 ) T(1−3) (Si 2.99 Al 0.01 ) O 12 (OH), corresponding to the end-member formula CaLaMn 3+ AlMn 2+ (Si 2 O 7 )(SiO 4 )O(OH). Unit-cell parameters are a = 8.9057(10), b = 5.7294(6), c = 10.1134(11) Å, β = 113.713(5) • , V = 472.46(9) Å 3 , Z = 2. The crystal structure of manganiakasakaite-(La) was refined to a final R 1 = 0.0262 for 2119 reflections with F o > 4σ(F o ) and 125 refined parameters. Ferriakasakaite-(Ce) occurs as small homogeneous domains within strongly inhomogeneous prismatic crystals, where other epidote supergroup minerals coexist [manganiandrosite-(Ce), "androsite-(Ce)", and epidote]. Associated minerals are calcite and hematite. Its empirical formula is A(1) (Ca 0.64 Mn 2+ 0.36 ) A(2) (Ce 0.37 La 0.17 Nd 0.06 Pr 0.03 Ca 0.35 0.02 ) M(1) (Fe 3+ 0.61 Al 0.39 ) M(2) Al 1.00 M(3) (Mn 2+ 0.64 Mn 3+ 0.33 Fe 3+ 0.02 Mg 0.01 ) T(1−3) Si 3.01 O 12 (OH), the end-member formula being CaCeFe 3+ AlMn 2+ (Si 2 O 7 )(SiO 4 )O(OH). Unit-cell parameters are a= 8.9033(3), b = 5.7066(2), c = 10.1363(3) Å, β = 114.222(2) • , V = 469.66(3) Å 3 , Z = 2. The crystal structure of ferriakasakaite-(Ce) was refined to a final R 1 = 0.0196 for 1960 unique reflections with F o > 4σ(F o ) and 124 refined parameters. Minerals 2019, 9, 353 2 of 15and 2 to the dollaseite group. Two additional minerals stand alone: zoisite, the unique example of epidote with orthorhombic symmetry, and åskagenite-(Nd), the unique example of epidote having a divalent anion dominant at the O(10) site. We herewith describe manganiakasakaite-(La) and ferriakasakaite-(Ce), two new minerals belonging to the allanite group. In this group, a trivalent cation, typically a REE, is dominant at the A(2) site, and a divalent cation is dominant at the M(3) site. According to the general guidelines for the nomenclature of epidotes [1], each distinct combination of dominant cations at the A(1) and M(3) sites deserves a proper root-name. In particular, the root-name "akasakaite" (after Masahide Akasaka, professor of mineralogy at the Shimane University) corresponds to the pair A(1) = Ca and M(3) = Mn 2+ [2]. Then, an adjectival prefix is appended to the root-name for the dominant cation at the M(1) (other than Al), and a Levinson suffix [3] is appended to the root-name for the dominant REE at the A(2) site. The names of the two new minerals are in keeping with the above guidelines, as they represent chemical variants of the mineral ferriakasakaite-(La), which was first described from Japan [2]. Both manganiakasakaite-(La) and ferriakasakaite-(Ce) were found in the Mn ore d...