.png){kind=icon}
.png){kind=icon}
Return
Babunaite-(Nd); Nd(AsO4) – the first REE-arsenate in the scheelite group from Nežilovo village area; North Macedonia: 150 years of the Mineralogical Society: Past Discoveries and Future Frontiers
.png){kind=icon}
OA
AI
I
J
M
S
P
G
E
DOI：10.1180/mgm.2026.10222.png)
.png){kind=icon}
.png){kind=icon}
Share.png){kind=icon}
Save
Abstract
En 中文
The new mineral; babunaite-(Nd) NdAsO4; was discovered in metasomatic rocks of the Mixed Series near the Nežilovo village in Northern Macedonia. These rocks are characterised by an unusual occurrence of Pb-Zn oxide ore mineralisation. This area forms part of the high-grade metamorphic region of the Upper Precambrian Pelagonian massif. Babunaite-(Nd) is an accessory mineral in pink schists; which mainly consists of Mn-bearing muscovite and quartz; with minor braunite. Accessory minerals are hematite; gahnite; almeidaite; långbanite; zircon; piemontite and piemontite-(Pb); nežilovite; Sb-bearing rutile; fluorapatite; As-bearing fluorapatite; gasparite-(La); chernovite-(Y); arsenoflorencite-(La). Babunaite-(Nd) forms single crystals measuring up to 70 μm in size. The transparent crystals exhibit an adamantine lustre and a pale-yellow colour. The microhardness of babunaite-(Nd) is VHN25 = 578(21) kg/mm2; equivalent to a hardness of 5 on the Mohs scale. The mineral is brittle and does not exhibit cleavage. The mean composition of the holotype crystal is as follows: (Nd3+0.39Ca0.14Th0.09Pr3+0.08La0.07Sm3+0.06Y0.06Gd0.05Ce3+0.02Eu3+0.01)Σ0.97(As5+0.95W6+0.05V5+0.01)Σ1.02O4. The calculated density is 5.918 g·cm–3. Babunaite-(Nd); with the general crystal chemical formula ABO4; has a scheelite-type structure and crystallises in the tetragonal I41/a space group: a = 5.1363(2) Å; c = 11.5764(8) Å; V = 305.41(3) Å3 and Z = 4. The main bands at 190; 348; 440 and 833 cm–1 are distinguished in the Raman spectrum of babunaite-(Nd). A synthetic analogue of babunaite-(Nd) is known; which forms under high-pressure and high-temperature conditions of 11 GPa and 1100–1300°C. The genesis of the Mixed Series rocks occurred under metamorphic conditions approaching the parameters of the kyanite–graphite subfacies; at which gasparite-(Nd) with the monazite structure should form. The formation of babunaite-(Nd) is associated with the stabilisation of its structure by a tungsten (W) impurity. It is the first arsenate phase containing rare earth elements (REE) in the scheelite group.
Keywords:
babunaite-(Nd)
new mineral
scheelite group
crystal structure
Raman spectrum
Nežilovo
North Macedonia
AI Summary
Key information extracted from the uploaded paper, including a brief overview, abstract, background, key highlights, visual analysis, and future outlook.
Journal
IF:
1.4
Papers:
178
Citations:
4.8K
View more organizations