Högbomite, a complex oxide of A1, Fe, Mg, and Ti, is an important constitutent of some iron ores and emery deposits as well as an infrequent accessory in aluminous high-grade rocks (e.g. Grew et al., 1987). The recent increase in reports of new localities (e.g. Rammlmair et al., 1988) suggests that högbomite may be more widespread than is generally perceived. We report here högbomite from the Aldan Shield, Eastern Siberia. This högbomite is remarkable for the wide variation in composition measured in a single thin section. Our report is only the second from the USSR of högbomite for which chemical data are given.

The first findings of Au and Ag tellurides (sylvanite and petzite) in sulfide-quartz ore of the Shi rokinsky ore and placer cluster located in the Sette Daban Horst Anticlinorium are described. These miner als were found for the first time at the gold deposits of East Yakutia. The chemical compositions (wt %) of sylvanite (23. in total) and petzite in total) are reported. Galena as a host mineral is associated with native gold, electrum, hessite, and stützite. The finding of Au-Ag and Ag tellurides provides evidence for the development of Au-telluride mineralization in the Sette Daban Horst Anticlinorium.

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