F ig . 7. Photomicrograph (oil immersion) of atokite and taimyrite intergrowth inside tetra-auricupride reaction rim on Pt–Fe alloy. Outlined section shows atokite relics within taimyrite. Sample II.

Fig. 12. Paragenesis of PGM (BSE images). ( a ) grains of isoferroplatinum Pt 3 Fe with inclusions of moncheite (Pt,Pd)Te 2 , vincentite Pd 3 (As,Te,Sn) and unnamed (Pd,Pt) 3 Sb; ( b ) grains of Pt–Fe alloys with atokite (Pd,Pt) 3 Sn; ( c ) intergrowths of stibiopalladinite Pd 5 Sb 2 , Au-Ag

Fig. 8. The associations of PGMs in the Mt. Rudnaya fine-grained ores; backscattered electron images. (A) Atokite crystals and Pt 3 Fe 2 rim around a coarser grain of tetraferroplatinum (sample RM 10). (B) Porous tetraferroplatinum grain with dissemination and overgrowths of smaller PGM grains

Fig. 1. A core of atokite-rustenburgite (at) is mantled by taimyrite–tatyanaite (tm), which is in contact with a heterogeneous Ag-Au alloy (ag). Oktyabr'sky deposit, Noril'sk. Back-scattered electron image. Scale bar equals 0.1 mm.

Fig. 10. Au-Pt-atokite (white) metacrystal in titanomagnetite of hornfelsed basalts. Medvezhii Ruchei Mine. BSE image.

Figure 6. Distinction between paolovite, (Pd,Pt) 2 Sn, and atokite/rustenburgite, (Pd,Pt) 3 Sn, despite interference from gold-rich alloy.

F ig . 8. Back-scattered electron images, showing a) intergrowth of atokite, mertieite-II [Pd 8 Sb 3 ] and telluroan sobolevskite [(Pd,Pt)(Bi,Te)] within tetra-auricupride rim (sample II) and b) intergrowth of taimyrite–tatyanaite with moncheite–insizwaite. Sample IV.

F ig . 1. Zoned intergrowth of atokite–rustenburgite (at), tatyanaite–taimyrite (tn) and heterogeneous Ag–Au alloy (Ag) (Ag 0.53–0.89 Au 0.47–0.11 ; energy-dispersion electron-microprobe data) among chalcopyrite (ccp), cubanite or isocubanite (lamellae within chalcopyrite) and pentlandite (pn

F ig . 3. A grain of atokite–rustenburgite (at), which consists of two domains and is surrounded by cryptically zoned taimyrite–tatyanaite (tm). These platinum-group minerals ( PGM ) are enclosed within a 1-mm grain of heterogeneous Ag–Au alloy (Ag), which is in contact with galena. The Ag–Au

F ig . 8. Skeletal (zoned) crystal of atokite–rustenburgite (at) associated with base-metal sulfides: chalcopyrite (ccp), pyrrhotite and pentlandite. A tiny grain (ms; white) at its contact is maslovite PtTe(Bi,Sb). Back-scattered electron image. Scale bar: 10 μm.

F ig . 9. Palladium and platinum X-ray maps of the zoned crystal of atokite–rustenburgite shown in Figure 8 . A general decrease in content of these elements is shown by the change in color: red (highest) → yellow (lower) → green (lowest). The crystal is 0.16 mm in the longest dimension.

F ig . 9. Palladium and platinum X-ray maps of the zoned crystal of atokite–rustenburgite shown in Figure 8 . A general decrease in content of these elements is shown by the change in color: red (highest) → yellow (lower) → green (lowest). The crystal is 0.16 mm in the longest dimension.

TABLE 4. RESULTS OF ELECTRON-MICROPROBE ANALYSES OF ZONED ATOKITE-RUSTENBURGITE § FROM NORIL’SK

in magnetite. (E) Atokite intergrown with other electrum and moncheite. (F) Atokite intergrown with electrum in magnetite. (G) Secondary framboidal native platinum in a secondary electron image. (H) Pt alloy surrounded by moncheite in chalcopyrite. (I) Elongated merenskyite in supergene violarite and magnetite

) grain in chalcopyrite, e) PGM aggregate (zvyagintsevite + sperrylite + atokite–rustenburgite) in cubanite, f) atokite crystal (At) in chalcopyrite, g) Fe–Pt alloy in a pyrrhotite–chalcopyrite aggregate, h) zvyagintsevite (Zv) veinlets in chalcopyrite. Gn: galena.

, palladoarsenide, tetraferroplatinum Pt(Fe,Cu,Ni), hongshiite Pt(Cu,Pd) and vincentite Pd 3 (As,Sb) including Au,Ag; (g) grain of vincentite Pd 3 (As,Te,Sn) with inclusions of atokite (Pd,Pt) 3 (Sn,As,Te), palarstanide (Pd,Pt) 5 (Sn,As,Te) 2 and Pt–Fe alloy; ( h ) intergrowths of Sn analogue of mertieite-I