Took this from McKearin and Wilson's classic book: "American Bottles & Flasks and Their Ancestry". The New Granite Glass Works existed from 1861 to 1871 according to this book. They operated in Stoddard, NH. Their advertising indicated that they would produce Glass Telegraph and Glass Lightning Rod Insulators! As to their production, with no marked LRIs to tie to them, it can be only guessed as to what they produced. Note their mention of Black Glass Bottles, and Preserve Jars. Probably black glass pin types and LRIs made?