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Gareth Evans' Home Page

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Metals, Minerals and Machines Homepage

Registered member since 1st Feb 2019

Gareth Evans has uploaded:
1197 Mineral Photos
64 Locality Photos
194 Other Photos

Gareth Evans has published 6 articles on

I am a retired Research Chemist with a passion for the chemical elements, minerals and machine tools.

For me the relationship between minerals, the chemical elements and machines is a very profound one. When asked why I collect minerals I simply point to my refined chemical elements and then to my machines – no further explanation is needed.

Thus in retirement I have three principle interests.

1. Collecting Chemical Elements and creating eye-catching displays of the Chemical Elements.

2. Machine tools, which I use to create working replicas of 19th century steam driven machines with an emphasis on machines used in the mines.

3. Collecting mineral specimens from world-wide localities, focusing on sulphides, sulphosalts and native elements.

Some of my early work with the chemical elements is shown in the following photographs - the blocks shown are 100 mm x 100 mm x 40 mm in size.

The d-block chemical elements of the Periodic Table Made out of Real Elements.

Note that these blocks were not commercially made. I created by hand every block shown, and I spent about two years perfecting the encapsulation technique using a non-acrylic based substrate. The substrate is not styrene based.

The final periodic table of the chemical elements made from real elements was so large I decided to create three smaller tables each displaying a specific group of elements. Thus there is a unique table for the s-block, p-block and d-block chemical elements. The gases are displayed using a different format – in plasma tubes. The plasma tubes enable me to energize the gas so it displays its characteristic colour – in the case of oxygen a warm blue.

Combining Art with Science - A light show

The tubes have a total length of 300 mm long. The top and bottom bulbs are 70 mm long with an ID of 18 mm, and they are connected by a glass tube 110 mm long with an ID of 12 mm.

To show the characteristic colours of the gases I had to design and build a suitable driver unit. The unit produces square pulses (+/- 12VDC) which are fed to a suitable flyback transformer to produce the necessary HV to energize the gases. The unit has other uses too – deactivating RFID tags!

Exciting the Noble Gases
Exciting the Noble Gases
Exciting the Noble Gases


I have begun making a new periodic element display. It will focus on the lanthanide metals. Shown is the display jar I have just recently made. The tube is made from borosilicate glass. It is 150 mm high with an internal diameter of 80 mm and a wall thickness of 2.5 mm.

I have chosen Tasmanian Oak (Eucalyptus) as the wood to be used in the display. It is classified as a hard-wood. I have done some preliminary wood turning on the metal lathe using a trepanning tool and a button tool. I could have used router bits but my HSS and Carbide lathe tools make short work of wood.


The wood has been sanded, sealed and varnished to look like ‘antique’ maple. I will also use some large O-rings to make a tight seal between glass and wood.

The display bottle shown in the photo will be the style used to display the more stable lanthanide elements – Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium and Ytterbium.

Shown in the photo below are my first two Lanthanide metal display bottles. The wood I used is called Tasmanian Oak, but it is actually a species of Eucalyptus. It is a hard wood that stains well, and the stain I used was maple. It was my intent to give the bottles a 19th century antique look – something you might have seen in the British Museum in the late 1800’s. One bottle will be used to contain the Ytterbium ingot (on the right in the photo), and the other will be used for Thulium.

The holes in the wood will have served two functions. Firstly, I needed the holes so I could secure and turn the wood in my metal lathe, and secondly the holes will be used to secure an internal display so the metals will appear as if they are floating in air. To conceal the holes I will use some wooden plugs that I will also make on the metal lathe. The last job is making the ‘antique’ labels.

It is interesting to note that when I first started this adventure with the chemical elements I had my fair share of the proverbial doubting Thomas, and some doubting Thomasina’s. Many were Academics at some Universities and some Museums. I was even described as a bit ‘nutty’ by some who felt that making quality periodic displays of the chemical elements at home was impossible.

So if you have a dream, do not let negative views hinder your progress.

Very soon I will also be making some quality minerals stands using the same techniques that I used to make the element bottles.



Shown are three of the six ‘apothecary’ style bottles that will contain and display the Lanthanide metals – Lanthanum, Cerium, Praseodymium, Neodymium, Samarium and Europium. Sadly no Promethium! The bottles are made from the finest quality borosilicate glass.

Each bottle is 190 mm high with a maximum internal diameter of 80 mm. The neck has an OD of 48 mm, and the glass has a wall thickness of 5 mm. They have been designed to withstand high vacuum. Europium is the only Lanthanide metal that will require special treatment, but it is certainly no more reactive to air and moisture than the element Lithium.

As it is my wish to display the Lanthanides with a beautiful and seductive metallic luster each metal will be sealed under an inert gas. I have a few ideas for a suitable gas-tight stopper that I will make out of Teflon or Delrin.


I have acquired all the lanthanide elements in quantities ranging from 500 grams to 1.2 kilograms so I believe it will be a noteworthy and significant display. Some examples of my collection of the lanthanide elements are shown in the photos below.

Samarium - 99.99%TREM - 600 grams
Combining Art with Science - Terbium
Ytterbium - 99,99%TREM - 900 grams

Now that the first periodic table of the chemical elements is almost complete I am moving ahead with a much larger version. I have called this version the ‘bullion’ series. Some examples of my work are shown below. The dimensions of each bullion bar are about 110 mm x 40 mm x 25 mm.

Combining Art with Science - The Bullion Series
Combining Art with Science - Antimony Ingot 1
Combining Art with Science - Bismuth

Shown is a Selenium Ingot I made for my new Periodic Table of the Chemical Elements – ‘The Bullion Series.’

It is a large one weighing 410 grams. It is 110 mm x 44 mm x 24 mm, and it looks beautiful. You will not see anything like it on the Internet for sale – I do original work for my amusement and my pleasure.


I am also interested in assembling a sub-collection of the chemical elements focusing on the allotropes. Carbon, Tin, Sulphur, Selenium, Phosphorus and Oxygen have some very interesting and visually appealing allotropes. Black phosphorus is one allotrope that is especially interesting – visually seductive and not too difficult to prepare.

Shown is a 50 gram sample of grey tin I prepared in the home lab. The starting material was a 50 gram mass of tin (99.99%) shavings. The individual shavings were about 2 mm wide and 30 mm long. Over the course of six weeks at -25 Celsius they have ‘almost’ completely disintegrated into the alpha form. This is more evident in the microphotographs (FOV 5 mm)

Alpha Tin

Grey Tin



Now we come to machine tools. The two principle machines I use are a lathe and a milling machine, along with an assortment of chucks, fixtures, drills, cutting tools and metrology instruments. With this assortment of tools I create replicas of 19th century mining machines. Shown below are a few examples of a Boulton & Watt style beam engine I completed in 2018. The full size version would have been used in the mines for either dewatering or winding purposes. The replica has the following dimensions: Length: 340 mm, Flywheel Diameter: 180 mm, Bore: 25.4 mm diameter, Stroke: 51 mm.

Raw Parts used to make Replica of 19th Century Winding Engine
Replica of a 19th Century Winding Engine
A Replica of a 19th Century Steam Powered Winding Engine - completed

I am in the process of completing a much larger stationary engine, and the dimensions of this one are; Height: 350 mm, Flywheel diameter: 190 mm, Cylinder Bore: 51 mm and Cylinder Stroke: 51 mm. Some photos of the build in progress are shown below. It is really a small scale engine – at 850 RPM it produces about 0.5HP.


Unlike the beam engine shown earlier, this engine is direct acting – the power is not transferred via a beam or rocker mechanism, but by the piston rod. The plan of the engine is shown in the diagram below.

Plan of Engine

The Engine is near completion and only requires running-in followed by painting and some artistic work with a wooden plinth to make it a museum quality piece.

There is something highly rewarding about creating things from scratch – to coordinate your mind, your eyes and your hands to turn what is just ‘rusty’ pieces of metal into a work of art. I have a passion for minerals, but I do not get the same thrill out of something that I had no part in creating. Not a criticism just an observation!

Below are some additional photos of the individual components after they had been machined on the metal turning lathe or the milling machine or both.



The replica of a 19th century winding engine is almost complete. I have finished the painting of the main parts and I have also constructed a plinth. The plinth is made of pine which I sanded, stained and polished with a maple finish. I mounted the engine on a 10 mm thick aluminium plate that I machined on the vertical milling machine using a corner rounding High Speed Steel (HSS) end-mill cutting tool. The aluminium plate will protect the wooden plinth from being distorted. I will be cladding the cylinder with small wooden planks, which will also be stained and varnished in maple. Many of the old beam engines used wooden cladding to prevent heat loss from the main cylinder – it is very visually appealing. I will also be making a suitable plaque using basic photo-etching techniques.



My fascination with minerals arose out of my interest in Inorganic Chemistry and my interest in the History and Technology of mining. Some of my sulphide and sulfosalt minerals are shown below. More can be seen by perusing my pages.

I have always had an interest in Copper minerals and so my collection is dominated by Azurite, Malachite and other copper species from the oxidized zone of some world-wide localities as seen in the following photographs.

My selection of native elements includes most naturally occurring elements with the exception of Gold.

I also collect oxides and some rare minerals, and I have included a few photos below.

Typical oxides

And some rare minerals


In the last few months I have become very keen on taking high-resolution photos of some of my minerals under high magnification.

The digital microscope I have was purchased with the intent to use it in my electronic circuit building projects so I could easily solder SMD parts. However I soon found applications for it in my mechanical interests (looking for hairline cracks in metal) and my mineral hobby.


An interest I have neglected in the past three years is electronics. As a young boy I was very keen on Ham Radio, and I still have fond memories of building equipment based on valves. I bought many kits from Heathkit, and my first Transceiver (HF Bands) was made by Collins.

I also have enjoyed making Radiation detectors, mainly Geiger-Muller counters but also Scintillator counters. About four years ago I started building a Gamma Ray Spectrometer, but only got as far as the Scintillator unit and a fully working Analog-to-Digital convertor.


Below is a photo showing the main boards of the Scintillator counter under test. In the background are the low voltage power supply and the Digital Storage Oscilloscope. In the foreground is the Photomultiplier tube (PMT), various controls, flashing LED and a very loud piezoelectric-speaker. In the middle are the main circuit boards and the high voltage (HV) power supply board.

The PMT is wrapped in Teflon tape, light proof paper and duct tape. This means the unit will be very sensitive to Gamma Rays, X-Rays and perhaps the odd high energy electron or positron. Alpha particles are not detected. For alpha particles I use a ‘common-garden variety’ Geiger-Muller (GM) tube. The various circuit boards shown in the photo can easily be adapted to GM tubes without any changes in components.

The HV board was constructed using predominantly surface mounted components (SMD). The other boards were constructed using through-hole components.

This unit works incredibly well. It can be used a standard scintillator counter for Uranium prospecting, and a scientific instrument if due care is given to the construction of the HV power supply and the PMT housing.


I tested a few scintillator materials, but decided to use BGO as it was especially suited to the detection of Gamma Rays.

Tail End of the Scintillator crystals

The Photomultiplier tube (PMT) used in the project was ex-EBay ($10) and came out of a PET unit that had seen very little use. The scintillator material I used was BGO (Bismuth Germanium Oxide) which I also obtained on EBay ($10). Fortunately the PMT came with the voltage divider attachment – the thing with the wires coming out in the last photo. I used a simple PIC16F628A ($2) microcontroller to count the pulses and place them (counts/sec) on a standard 2 x 16 LCD ($3). The board containing the Microcontroller also contains a few other circuits too, but nothing at all difficult to make.

Finding Radioactive Minerals
Finding Radioactive Minerals
Finding Radioactive Minerals

The high-voltage power supply was remarkably simple and inexpensive to make. I made a high frequency (24 kHz) oscillator out of two transistors ($3) and a couple of capacitors ($0.8). The AC voltage so produced was fed to a step up transformer ($1.80), the sort used in CCFL tubes. The HV AC output was fed to a network of HV fast switching diodes ($3) and capacitors ($2) to produce a very clean and stable HV DC voltage to power the PMT. A portion of the HV output was fed back to a control IC ($3) via a 20 MOhm voltage divider ($2) so the output was kept stable under load.

I have also included some Oscillograms – one for a Torbernite specimen in my collection, and another for an Am-241 source.

Finding Radioactive Minerals
Finding Radioactive Minerals

The unit was made at home on the kitchen table, and I also made the PCB’s (Printed Circuit Boards) using material purchased from a local hobby store called Jaycar. The Scintillator Counter works very well considering how inexpensive it was to make.

The next part will be to construct a suitable Analog-to-Digital convertor along with a suitable Microcontroller to convert the unit into a Gamma Ray Spectrometer.

Messaging Statistics

Total messages posted:209
New threads started:7
First message posted:15th Apr 2019
Latest message posted:15th Oct 2019

My Latest Discussions and Replies

6mCOLLECTING THE CHEMICAL ELEMENTS Posted by Gareth Evans. 96 replies in Education.20hPseudomorphs second incarnationPosted by Rolf Luetcke. 10 replies in General.21hCollected with your dirty hands - Volume IIPosted by Matt Courville. 101 replies in Field Collecting.22hThe Nature Thread Part IIPosted by Russ Rizzo. 104 replies in General.2dBest photographs of specimens larger than 1cmPosted by Rudolf Hasler. 507 replies in Mineral Photography.2dCheaply testing specimens for radiationPosted by Ali U.. 22 replies in Education.2dCan fluorite be dangerous ?Posted by Gorge Jones. 20 replies in General.3dgranites and the nature of proofPosted by Tony Peterson. 8 replies in Photos.4dCleaning a "dusty" Mindouli DioptasePosted by Tama Higuchi. 21 replies in Techniques for Collectors.4dPeabody Museum, Yale University, New Haven, Connecticut, USAPosted by Tony Albini. 2 replies in General.1wWhat are the minerals to be buying nowadays?Posted by Owen Tolley. 31 replies in General.1wLazurite Crystals for sale on eBay real deal?Posted by Owen Tolley. 13 replies in Fakes & Frauds.1wA Poor Man’s Mineral MicroscopePosted by Gareth Evans. 19 replies to an article.1wMissouri Chalcopyrite Iridescence?Posted by Steve Hardinger. 14 replies in General.2wNeed help with Mibladen localitiesPosted by Steve Stuart. 3 replies in General.2wReason for User Gallery OnlyPosted by Charles D Young. 52 replies in Improving SmithsonianPosted by Larry Maltby. 24 replies to an article.2wThe Lanthanide metals – Another Museum display for the Home Office Posted by Gareth Evans. 2 replies to an article.2wDo I label as Hematite?Posted by Tama Higuchi. 5 replies in General.3wPseudomorphsPosted by Rolf Luetcke. 470 replies in General.

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