Legrandite is one of my favorite minerals, first of all, is a rare specimen with a single worldwide location, and that is the "Ojuela Mine" in Mapimi, state of Durango in Mexico, a mine I had the chance to visit several times during 1985, and from where I collected other related minerals, such as Adamite, cobaltoadamite, goethite, malachite, hemimorphite, wulfenite, etc.
The name "legrandite: is in honor of the Ojuela's first mine superintendent in the late 1800's, Monsieur Legrande, a mining engineer from Belgium.
The most beautiful legrandite specimen I've ever seen, was in what is now the Museum of Mineralogy in Tehuacan, Puebla, founded by a passed friend of mine Mr. Miguel Romero (Mexican Congressman in the late 80's). The years I taught Mineralogy (1987-1989), I used to take my Mineralogy students to see Mr. Romeros' mineral museum, and they loved the beauty, variety and quality of this collection. Those trips were very educative field trips that I of course enjoyed as well.
This is the URL to the museum in case you'd like to visit: http://puebla-tehuacan.wexico.com/Tehuacan/Museo/index.html, I plan to do that as soon as feasible.
Zn2(AsO4)(OH)·(H2O) - Hydrated Zinc Arsenate Hydroxide
Environment: Secondary mineral in zinc ore bodies.
Locality: Ojuela mine near Mapimi, Durango.
More data: http://webmineral.com/data/Legrandite.shtml
I own some of these specimens, one I consider of superb high quality, will publish the picture one fine day.
In the meantime, have a good day, and I see you on my next post.