The XRD diffraction patterns of these layers showed predomination of the phase of monoclinic silver sulphide
acanthite [Ag.sub.2]S.
Although individual crystals in a new lot of specimens offered by Horst still are small (to 2 mm or so), they are of a brighter red, and look somehow much more promising for the future: the proustite occurs as solid druse coverages over gray
acanthite, and very nice matrix thumbnails and miniatures could be had in Munich for 40 to 120 euros.
But the basic equations (Bakewell, 1984) for the patio processing of
acanthite were as follows:
Soon he began shipping some extraordinary silver mineral specimens back to New York, including the largest and best polybasite specimens known, large clusters of "poker chip" stephanite crystals, fine acanthite specimens and a few very fine pyrargyrite specimens.
The individual pockets have distinctive ore mineralogy, but the bulk of the mineralization consists of acanthite, polybasite and stephanite.
The family sent Schmitter a number of fine mineral specimens in the early 1970s, and he passed them along to Miguel; included among them was what may be the world's finest acanthite.
Along with the aforementioned acanthite from the Las Chispas mine, Arizpe, Sonora (believed by many to be the world's finest example of the species), the Romero collection also held an extraordinary jalpaite (A[g.sub.3]Cu[S.sub.2]) from the type locality at Jalpa, Zacatecas, and a silver specimen mined in the early 1800s at Pachuca (this is one of the earliest surviving Mexican mineral specimens).
Since then Fresnillo has become one of the world's greatest silver districts, and has also yielded superb specimens of crystallized pyrargyrite, stephanite,
acanthite and polybasite.
There seems to be a bit of a locality-mystery surrounding some new Chinese specimens of
acanthite offered by both Rob Lavinsky and Dr.
In the previous "What's New" column in the Mineralogical Record the new strike of
acanthite and native silver specimens from China, first brought into the U.S.
An exciting occurrence of wire silver on
acanthite also turned up at the show.
All these new finds were from Morocco, including a few of the erythrites, some nice roselite from the Agoudal quarry, Bou Azzer district, some cute loose clusters of azurite from Kerouchen, and a few
acanthites from Imiter.