Abstract
Holtedahlite occurs in a serpentine-magnesite deposit at Modum in association with althausite and (OH,F) apatite. It is colourless, transparent, has a vitreous lustre, occurs in massive form and shows no cleavage. The Mohs' hardness is 4 1 2 −5 ; specific gravity 2.94(2) (Berman balance), calculated density 2.936 g/cm 3. It is uniaxial negative, ω = 1.599(1), ϵ = 1.597(1). Chemical analysis with the electron microprobe and separate determinations of CO 2 and H 2O give a formula close to Mg 2PO 4OH or more specifically (Mg,Na) 2(PO 4, CO 3OH)(OH,F). Holtedahlite is hexagonal, α = 11.188(2), c = 4.975(1) A ˚ , V = 539.3(3) A ˚ 3 Z = 6 , space group P321, P3m l or P 3m l . The strongest lines in the X-ray powder pattern are (in Å, with intensities and indices): 3.722(90) ( 11 21 ), 3.475(50) ( 20 21 ), 3.234(30) ( 30 30 ), 2.796(30), 2.438(100) ( 22 41 ), 2.177(30) (2.177(30) ( 40 41 ), 1.859(30) ( 22 42 ). The infrared spectrum shows the presence of OH −, CO 3 2−, and PO 4 3− and indicates an O-H… O distance of ca. 3.02 Å.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
