herderite

from The Century Dictionary.

• noun It occurs also at Paris and Hebron, Maine. It is shown by Penfield to be monoclinic (pseudo-orthorhomnic) in crystallization, with a composition expressed by the formula Ca [Be (F, OH)] PO₄. Purefluor-herderite has not yet been observed; the mineral from Paris is a hydrofluor-herderite, and that from Hebron a hydroherderite.
• noun A rare fluophosphate of beryllium and calcium, occurring in white or yellowish transparent crystals in Saxony, and at Stoneham in Maine, U. S.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Min.) A rare fluophosphate of glucina, in small white crystals.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun mineralogy A monoclinic-prismatic mineral containing beryllium, calcium, fluorine, oxygen, and phosphorus.