FMF - Friends of Minerals Forum, discussion and message board

[silvia]

A very aerial group of very sharp thin tabular Baryte crystals, transparent, bright with an intense reddish-yellow color on a matrix of white crystallized Quartz with groups of very bright cubic Pyrite crystals, and partially coated by small white aggregates of Quartz microcrystals and Pyrite crystals.

[Michael Shaw]

[silvia]

[silvia]

This is an important specimen of unusually large size and visual impact, consisting of highly lustrous metallic-gray, Skutterudite crystals to 5 cm in a huge 3-dimensional cluster. The matrix view of the specimen reveals oscillatory zoning during deposition and there are several other minerals (unidentified) growing within the matrix.

[Carles Millan]

[silvia]

A cabinet sized sample of a lustrous pyrite floater "sun" formed between an ancient bed of shale and clay near Sparta, Illinois.

[Roger Warin]

Hello Silvia,
Can you explain this growth?
Thanks.

[silvia]

I am just a retired science teacher. I think you might be able to explain it better than I.

[Michael Shaw]

The July/August 2022 issue of Rocks and Minerals has a very good in depth article explaining the growth of pyrite suns. Rocks & Minerals Vol. 97(4): 330-346.

[silvia]

[silvia]

The specimen contains a super-sharp pseudo of Malachite after Azurite, and the sharp, tabular rhombohedral habit of the original Azurite has been preserved superbly by the Malachite, to the point that you can see each edge and variation in the original crystal. The Malachite has an aesthetic chatoyant deep forest-green luster. The large prominent rhombohedral crystal of Malachite after Azurite is 53 mm wide.

[silvia]

This is an attractive specimen of Azurite on matrix from the Milpillas Mine in Mexico. The piece features lustrous, deep electric blue well-formed crystals of Azurite associated with minor mint green Malachite sitting on contrasting matrix. The matrix is composed of Dickite, but the Azurite rests on what could be a primary Copper mineral, perhaps Chalcocite but the identity remains unknown. My favorite aspect of the piece is that the Azurite crystals are incredibly gemmy showing an electric indigo hue, a feature that has defined Azurite from the Milpillas mine.

[silvia]

Native Copper

A fantastic display of dendritic Native Copper from the famous Milpillas mine in Mexico. The specimen has an excellent natural patina of coppery milk chocolate, with some thin patches of Cuprite on some of the larger Copper crystals. The Copper crystals show complex and modified forms of the octahedron, with some crystals developing to about 5 mm across. The white patches are Quartz.

As far as collecting Milpillas minerals are concerned (indeed all minerals) we have endeavored to obtain quality material from all parts of the ore-body. We want our collection to highlight the unique geochemistry of the ore body. We are first and foremost scientific collectors, and we consider great aesthetics to be just icing on the proverbial mineralogical cake.

[James Catmur]

Welcome back Silvia, I noticed that you had stopped posting your great photos

[silvia]

Hello Bob [James]:

Many thanks for your kind words, but I think full credit should go to my camera.

We have been doing a lot of travelling and purchasing minerals from fellow collectors, which we still have to catalogue and photograph. My partner also acquired a stunning 1 kilogram ingot of high purity Germanium and a large boule of high purity Silicon for his chemical element collection. He plans to polish and etch the Germanium ingot.

However mineral collecting is not my primary interest. My main passions, like those of my partner and one of our four children, are chemistry and astronomy. My partner also has a passion for RF electronics and mechanical engineering.

So if I disappear for a few weeks or a few months it is because I am probably doing some very ‘nerdy’ things with my partner and our children.