福島県石川町猫啼産クサビ石の結晶形

An account of the crystal forms of titanite is given herein. The titanite is derived from presumable border zone of pegmatite exposed on Nekonaki，Ishikawa Town，Fukushima Prefecture，Japan. The size of well formed crystals ranges from 4 mm to 5mm in length. The forms were ascertained by means of a two-circle goniometer and the result is as follows：the faces O01，100，310，102，111，112，and 132 are detected，in which，however，310 and 132 are rare. The single crystals are distinctly flattened to 102，and the common faces are 102，110，112 and 111. The twin crystals with having twinning plane 1OO seem to be the peetrating relations rather than simple contact relation of them.