Compositionally unusual Ba-rich micas have been found in the Franklin Marble at the Lime Crest quarry and at Sterling Hill, both in New Jersey. At Lime Crest, coarse calcitedolomite marble is cut by very small veins containing green and colorless micas, albite, fluorite, pyrite, and chromian rutile. Large green muscovite flakes are superficially similar to comparable barian and chromian muscovite from Isua and Malene, West Greenland: BaO contents range up to 12 wt% (about ⅓ of the A site), and Cr2O3, contents, though typically about 1 wt%, can be as high as 4 wt%. Smaller muscovite grains in recrystallized marble on vein margins have the lowest Ba and highest Cr contents. Barian, fluorian phlogopite, also on vein margins, has about 3 wt% of both BaO and F and very low total Fe. Formation of these Ba-, Cr-, and F-rich minerals is clearly related to vein formation, and vein-forming fluids were presumably the transport agents for the elements that are not typically concentrated in the marble.

At Sterling Hill, Ba-rich biotite has been found in an augite-willemite-gahnite-sphalerite-calcite skarn. This biotite is bright orange in plane-polarized light and contains from 4 up to about 25 wt% BaO. Changes in concentration of a number of other elements are correlated with Ba content. The micas highest in Ba are also high in total Fe and in Fe/Mg ratio, and qualify to be called anandite. They differ spectacularly from previously reported anandite, however, in having about 7 wt% Cl, and they are by far the most Cl-rich micas yet described. The Ba-rich micas also are higher than low-Ba micas in content of NiO (0.24 vs. 0.10 wt%) and MnO (2.3 vs. 1.7 wt%) but lower in content of ZnO (4–5 vs. 8–9 wt%) and TiO2 (0.7 vs. 1.5–2 wt%). Although the whole barian mica compositional range can be seen in a single thin section, there is no textural evidence to indicate chronology of formation. A scenario has been constructed in which isochemical metamorphism of the skarn protolith resulted in formation of Ba-rich sheet silicates and sphalerite as a result of thermal breakdown and reduction of hydrothermal barite in the presence of hydrothermal Zn- and Mn-rich ore minerals, minor admixed detrital sediments, and pore fluids. Rapid depletion of the small reservoirs of Ba, Fe, and Cl apparently resulted in subsequent formation of biotite much poorer in Ba, Cl, and Fe. These micas appear to have survived a granulite-grade metamorphic peak, although they may have been reconstituted during cooling.

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