LAVENDULAN


NaCaCu5(AsO4)4Cl · 5H2O,
sodium calcium copper arsenate chloride hydrate




Lavendulan from Sterling Hill was first recognized in 2014, when a specimen of a patchy, pale greenish-blue mineral on ore, formerly labeled aurichalcite, was subjected to analysis because it failed to effervesce in hydrochloric acid, thereby casting doubt on its identity.  X-ray diffraction data for the mineral proved a good match for lavendulan, as did chemical data obtained through energy dispersive spectroscopy.  Lavendulan was then added to the list of local mineral species.

More specimens of lavendulan may reside in collections, but given the large number of secondary copper species, many of which are some shade of blue, the possibility of recognizing the mineral on sight is remote.  The discovery specimen (LAV1) was found on 1200 level in the Sterling mine, on a piece of typical granular willemite-franklinite-calcite ore.

References

Cureton, Forrest, Nikischer, Tony, and Kampf, Tony (2014), Lavendulan from the Sterling mine, Ogdensburg, New Jersey.  Mineral News, vol. 30, no. 5, p. 1-2, 7 [Adds lavendulan to the local species list on basis of XRD and SEM/EDS analyses]

King, V.T., King, N.E., Betancourt, P.P., Bostwick, R.C., Chin, Peter, Hecht, T.J., Kuitems, S.M., Moritz, H., Nemetz, J.D., Nikischer, A.J., Sanford, Stephen, Van Fleet, J.A., and Verbeek, E.R. (2021), The Mineralogy of Franklin and Ogdensburg, New Jersey—A Photographic Celebration. Privately published, 1400 pp. [Photomicrograph of a lavendulan specimen from Sterling Hill shown on p. 955]



Images




Thin, patchy, pale blue coating of lavendulan, in tiny spheroids on granular willemite-franklinite-calcite ore.
Tony Nikischer
A thin, patchy, pale blue coating of lavendulan, in tiny spheroids, on granular willemite-franklinite-calcite ore. The associated green mineral has been sight-identified as possible cuprian adamite. Also present is reddish-brown, microcrystalline sarkinite and a black coating tentatively regarded as tenorite.

The history of this specimen is recounted in detail in the reference given above. It was found on the 1200 level in the Sterling mine, date unknown, and in 1979 was sold by Fred Parker (Parker Minerals) to Robert Trimingham, a systematic mineral collector from California. It was then regarded as aurichalcite, but Trimingham noted the failure of the mineral to react to hydrochloric acid and recommended further study. Upon Trimingham's demise in 2013, the specimen passed into the hands of Rock Currier (Jewel Tunnel Imports) and was then sold to Forrest Cureton. Cureton noted that the mineral, upon magnification, did not resemble typical aurichalcite and submitted it for XRD and EDS analysis, which proved the mineral to be lavendulan. The original specimen measured 7 x 5 cm but was later trimmed to its present size of 4 x 2.5 cm; a smaller trim piece, also bearing lavendulan, as of 2014 was in the collection of Mark Feinglos. Another specimen from the collection of Steven Kuitems is pictured in King et al. (2021).

Identifier: LAV1a
Locality: 1200 level, Sterling mine, Ogdensburg
Specimen size: 4 x 2.5 cm as photographed