Hi Modris, looks like a dark brown uvite from the looks of the termination and poikiolitic texture of broken crystals. It is very common to have the Franklin, NJ uvites incorporate the calcite into the crystals as they form. That's why you should not etch them out with acids. Steve.
Shows you how many uvites I've found at Franklin! At least you taught me to look at the cleavage from that last fiasco. So I was at least thinking tourmaline. But I still have trouble visualizing that second xl as a uvite ... I need to ponder Dunn's diagrams some more.
According to the entry for uvite in Dunn's "Franklin and Sterling Hill, New Jersey ..." (p.425), 'Uvite was redefined and established by Dunn et al. in "Uvite, a new (old) common member of the tourmaline group and its implications for collectors" Meneralogical Record, 8, 100-108 (1977).
Perhaps Steve or Chet know of something more recent.