Melteigite (Ijolite) intrusion adjacent to fenitized country rock (telemark gneiss), Fen complex. The intrusion consists predominately of a dense mat of anhedral augite prisms, some zoned, with abundant euhedral titanite (sphene) and fine-grained mixtures of muscovite and (likely) aegirine, likely altered nepheline.

The Telemark gneiss has been fenitized, evidenced by the perthic K-feldspar with weakly albitized borders. Some pyrite. A feature that appears to be a vein consists of carbonate (likely calcite) and chessboard albite.

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