Specimen data for Anthophyllite.

Tom Mortimer catalog number: 1885

Identification method: Identification method: EDS analysis.



Dianne R. Nielson's Dartmouth College Doctorate Thesis Metamorphic Diffusion in New Hampshire Soapstone Bodies and Flecky Gneisses, 1974, notes the presence of anthophyllite veins occurring within the talc body at Canterbury, NH. EDS analysis of my samples collected in 2012 indicated were the anthophyllite referenced in Nielson's thesis.
The mindat anthophyllite formula is given as the pure Mg end-member, {Mg₂}{Mg₅}(Si₈O₂₂)(OH)₂. Many authoritative references, such as Deer, Howie, and Zussman give a formula indicating Fe substitution: (Mg, Fe)₇[Si₈O₂₂](OH)₂, which is likely almost always the case in "real-world" specimens, such as this one where the analysis shows ample Fe.