FMF - Friends of Minerals Forum, discussion and message board

[Lumaes]

Featured below is another of my “ore” minerals, and in my opinion it is the most beautiful sulphide in the mineral kingdom. It is Covellite and its simple formula of CuS hides just how interesting and complex its structure is. It has the most amazing blue colour coupled with a beautiful iridescence. I have tried to capture these features in the photos below. The matrix is quartz (I surmise) with abundant pyrite. It hails from the Leonard Mine, Butte, Butte District, Silver Bow County, Montana, U.S.A. It is 5 x 5 x 5 cm. It was a gift from Jack Lowell.

[Lumaes]

Below is another piece from Peru. It is a small plate of Pyrite with Tetrahedrite. There is a large Pyrite crystal to the right and a few smaller ones scattered around the piece. It also shows a latter generation of microcrystalline Pyrite. The luster on these Pyrites is just amazing – mirror like reflections. Beautiful! It hails from the Quiruvilca Mine, Quiruvilca District, Santiago de Chuco Province, La Libertad Department, Peru. It is 9 s 6 x 3 cm.

I have ordered some Dremel parts - wood routers and I have been out shopping for some nice wood and a few acrylic sheets. Once I have got all my stuff together I am going to make a few really top notch wooden stands and when I am happy with the finished product I will post the plans, perhaps even a video so other may be able to duplicate my work.

[Lumaes]

Below is a book I have in my technical library and one I can highly recommend. It is a book every serious mineral collector should possess. It is the holy grail of Inorganic texts. The left hand photo shows the title and authors and the right hand one shows a nice discussion on Realgar and Orpiment. Sadly Dr Alan Sharpe passed away a few years ago. The structure of Realgar is interesting and gives clues as to why it is a very unstable mineral in the presence of visible light . Look at the cage structure and the consider the stability of the As-As and As-S bonds. To get the full story I suggest getting the book.

[Lumaes]

Below is another of my “ore” minerals, and this one is perhaps among the most colourful minerals you can get. I have included two close-up shots. Regrettably it is also very fragile and there will always be few broken crystals. It hails from the Adelaide Mine, Zeehan Mining District, Dundas, Tasmania, Australia. 10 x 7 x 7 cm.

It is also an interesting mineral because other members of the same type PbMO4 exist. Chromium belongs to a class of elements in the periodic table called group six. The other members of this group include Molybdenum, Tungsten and the artificial element Seaborgium. The naturally occurring elements form what is known as a “triad” and members of this triad have similar physical and chemical properties but also a lot of differences too. Below is a table showing the other mineral members of this triad – Wulfenite and Stolzite. Compare other element groups, Copper, Silver, Gold and Sphalerite with Greenockite and Cinnabar. There are many more examples too! This is what I try to do with my collection – base it on the Periodic Table of the Elements.

[Lumaes]

This is another of my Chinese Cassiterites but this one comes from Yaogangxian. It is composed of very sharp Cassiterites with Arsenopyrite, mica and quartz. I surmise the Cassiterites are twinned. It hails from the Yaogangxian Mine, Yizhang County, Chenzhou Prefecture, Hunan Province, China. 9 x 6 x 4 cm.

[Lumaes]

It is perhaps appropriate that I post the picture of my Sphalerite and Arsenopyrite combo that I had analyzed some months ago. It is a pretty piece and the sphalerite has the most unusual, yet natural bluish colouration. It hails from Yaogangxian Mine, Yizhang County, Chenzhou Prefecture, Hunan Province, China. 8 x 5 x 2 cm. It is one I will probably give away to help another collector build up their suite of Chinese minerals.

[Lumaes]

Featured below is another Chinese Calcite, this time on Pyrite. The habit of the calcite crystals is reminiscent of those from the Cumbrian Iron Field in England. It is a large stalagmite of calcite but in the lower right hand side there are a few individual crystals that have the most amazing light yellow hue and they are very gemmy. It hails from Shangbao Pyrite Mine, Leiyang County, Hengyang Prefecture, Hunan Province, China. 14 x 6 x 5 cm.

[Lumaes]

Featured below is one of my Stibnite clusters. With this photograph I decided to go “retro” and post it as a “black-white” image. Stibnite has a lot of sparkle but not much colour and I had a hard time reducing the amount of reflection that came off the crystals. The crystals are like long slender mirrors. It hails from Xikuangshan Mine, Lengshuijiang, Loudi Prefecture, Jiangxi Province, China. It is about 14 x 14 x 9 cm and there is a small amount of matrix present.

[Lumaes]

Featured below is another of my Elba hematite specimens. It is again microcrystalline hematite with pockets full of the most lusterous hematite crystals. The crystals occur as thick blades and the largest is about 1.8cm in width. There are also some clusters of milky quartz crystals. It hails from the Terranera Mine, Port Azzurro, Isola d' Elba, Livorno Province, Tuscany, Italy. 12 x 9 x 9 cm.

[Lumaes]

Featured below is another of my Florence Mine hematites – variety Specularite. The photo does not reveal its true beauty. It consists of thousands of blades of the most lusterous hematite and to show this I have included a few close-up photos of the crystal groups. It hails from the Florence Mine, Egremont, West Cumberland Iron Field, North Western Region (Cumberland), Cumbria, England, United Kingdom. 14 x 10 x 1.5 cm.

[Lumaes]

Feature below is one of my very first Chinese minerals. It is a small plate of arsenopyrite crystals on arsenopyrite. The crystals have the most amazing metallic luster and very nice form. I find the “www.spam.org comb” habit on some of the crystals absolutely enchanting. It hails from Yaogangxian Mine, Yizhang County, Chenzhou Prefecture, Hunan Province, China. 7 x 6 x 1.5 cm.

[Jordi Fabre]

[Lumaes]

Featured below is another Chinese Arsenopyrite. The yellow crystals coating some of the Arsenopyrite crystals are inferred to be siderite, but not yet proven. The specimen is a solid mass of Arsenopyrite on which lovely crystals of Arsenopyrite have grown. It hails from Dachang Polymetallic Ore Field, Nandan County, Hechi Prefecture, Guangxi Zhuang Autonomous Region, China. 9 x 6 x 5 cm.

[Lumaes]

Featured below is another of my Peruvian Pyrites. I find the varied forms of pyrite most interesting, and so it is a good mineral to acquire. The piece below hails from the Huanzala Mine, Huallanca District, Dos de Mayo Province, Huánuco Department, Peru. 8 x 6 x 6 cm.

[Lumaes]

Featured below is a schorl I posted a few weeks ago. I decided to take a few more shots. I think it is a ‘beauty.” It has a great luster, mirror-like in fact and the terminations are just great. It also has a few interesting surface features. In the last photo is a highly symmetrical terraced pit. When I asked about this feature it was suggested that they once supported quartz crystals, but I am not sure. It hails from Erongo Mountains, Usakos and Omaruru Districts, Erongo Region, Namibia, Africa. 6 x 5 x 4 cm.

[Lumaes]

Featured below is another of my Peruvian pieces. This time it is Sphalerite on Quartz. The crystals have the most amazing luster and shapes as can be seen in the two close-up photos. This sphalerite is the black opaque variety due to iron. I am fortunate to have sphalerites in a wide range of colours and shapes. This piece hails from the Animon Mine, San Jose Huayallay District, Daniel Alcides Carrion Province, Pasco Department, Peru. 14 x 10 x 8 cm.

[Lumaes]

NATIVE GOLD

Let’s go Gold Prospecting!!

I have always wanted a Pulsed Induction Metal Detector but they are too expensive for a humble retiree to buy. Some can cost as much as $5000USD, so what does one do? Build one of course! Below is my Pulsed Induction Metal detector made at home - some parts were salvaged from old Computer monitors and some were bought quite inexpensively from Electronic Parts supply companies, and there are thousands of them on the Internet. The total cost was about $100USD, and it works as good as the $5000 versions. It was based on a Russian Home-made design. So I repeat, this is not a toy but a unit equal in performance to many commercial designs that cost $1000’s. It uses a microcontroller, which are easy to program.

[Lumaes]

Featured below is a lovely specimen of Chalcopyrite on Quartz. It is also possible to see some metallic grey hairs of what we surmise to be Bismuthinite - but not proven by analysis. The Chalcopyrite crystals have an amazing luster and the colour is a beautiful gold with a hint of green. It hails from the Yaogangxian Mine, Yizhang County, Chenzhou Prefecture, Hunan Province, China. 7 x 4 x 4 cm.

[Lumaes]

This is the other side of the one posted above It is also possible to see some metallic grey hairs of what we surmise to be Bismuthinite - but not proven by analysis. The Chalcopyrite crystals have an amazing luster and the colour is a beautiful gold with a hint of green. It hails from the Yaogangxian Mine, Yizhang County, Chenzhou Prefecture, Hunan Province, China. 7 x 4 x 4 cm.

[Lumaes]

Bismuthinite is a very interesting mineral, and is part of a neat family of minerals belonging to Group 15 of the Periodic Table of the Elements. The other notable sulphides are Orpiment and Stibnite. So far I have several display quality pieces belonging to this Group of elements and I am always on the lookout for a confirmed display specimen of Bismuthinite, along with the Native Elements of course. Bismuth is a very interesting element in that it is naturally radioactive, but the half life is so long ca. 1.9 × 1019 years it is hard to detect a radioactive decay. Its half life is longer than the estimated age of the universe.