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They are fun coins and a cool link to history!

Haha, I have a related degree and it took me many years to fully appreciate how all the pieces of mineralogy, crystallography, optics, and chemistry fit together. Once I finally understood this I wanted to try and find ways to teach others since I think these concepts are important in understanding the world around us. The people who originally put these pieces together were geniuses, I am just trying to recycle their work into a new way of teaching in a new format. So am I a doorknob or a genius...I am a shiny doorknob reflecting the knowledge of others!

It's a synthetic corundum crystal with windows cut into it, it doesn't look much like a natural corundum crystal. The Optical Mineralogy Big Picture video shows off a natural corundum crystal and and another synthetic corundum crystal to illustrate how forms, symmetry and optics are related. Cheers!

Thanks again for your support!

There's so much more to all of these bits of history isn't there! I'm sure someone somewhere has an awesome colonial coin collection that could be useful for making a detailed history of coins, the colonies, and the Revolutionary War. There's definitely room for lots more nerding!

Glad you like them, thanks!

Glad you enjoyed it. I like coin collecting as a way to travel through history and to different places. It is a great way to learn!

Haha, what I'm hearing is...there's more opportunity for additional nerdy mineral videos! Anything in particular you'd like a deeper dive on?

Thank you, and I will definitely make more!

I'm not sure to be honest, usually whenever there is a war people tend to hoard coins with metal content. The WW1 era coins are fairly common, but I don't know about the balance of banknotes and coins in the economy. Good question!

@@willsnellius like in Britain banknotes weren't used much up till the 50s I believe

Gold coins were called in during 1914, the same as Britain. Gold was wanted for war essentials. The same in Germany, and the rest of Europe.

My pleasure! It was fun using the coins to think about history.

I decided to stick with copper/bronze for this round. It'd be fun to go back further in time with the silver pennies, but that would also get pricey!

The shillings would be a good set and go back much further in time than the copper pennies. They get pricey for the older ones though!

To get an idea of pricing I usually use the Numismatic Guaranty Company's (NGC) World Coin Price Guide tool. However, the prices tend to be very "optimistic", so I assume about 50% of the listed value. That year has a very high mintage, so unfortunately I don't think it would be worth too much unless in mint state. Hope this helps!

Glad that you liked the video. Australian pennies sound like an interesting set, I'd have to look a bit more into the history of Australia to see. What sort of story do you think could be told with them? Also thanks for the offer of some pennies, let me see if I can dig up a full set of Australian penny design changes with what I've got here already. I've been needing to do some organizing for quite some time!

Pennsylvania doesn't get a mention on either list? That's rough...the only thing worse than being talked about is not being talked about.

I'm not a gemologist, rather a geologist, so I've never actually worked with diamonds. Here's some thoughts based on theory though. Diamonds are isometric minerals, meaning they should be isotropic. So no pleochroism visible in plane polarized light, and they should remain extinct with crossed polarizers. There are many reasons why diamonds might behave a bit anomalously including stress, inclusions and a very high refractive index that might lead to more light bouncing off of surfaces within the crystal. Hope this helps!

eBay has worked for me to sell coins in the past, but you have to do some research on your coins beforehand to know how to price them.

Thanks, and I'm glad you enjoyed these videos!

Prices fluctuate, but the whole set could be purchased for around $120 when I did this. The earlier coins were much more expensive ($20 -$30 each) than the later coins. Getting the earlier coins in the series at higher grade would be significantly more expensive.

You are right that Napoleon III bravely took to the battlefield during the Franco-Prussian war at a time when most leaders no longer did such things. That quote is from Karl Marx, so not someone known for their sympathy for imperial leaders. Also it would be hard to compare to Napoleon I!

@@willsnellius certainly! He was very different from his uncle and he certainly deserved a better reputation for his many achievements.

I usually use the NGC coin price guide to get a sense of the value of a coin. www.ngccoin.com/price-guide/world/ The values shown are for the higher end of retail sale, so expect significantly less, 50% of the stated value at best.

You are right, there are many variations that are not shown in this video, so I don't want folks to think these are the only British penny coins out there! There's definitely room to do additional videos!

Prices fluctuate, but the whole set could be purchased for around $120 when I did this. The earlier coins were much more expensive ($20 -$30 each) than the later coins. Getting the earlier coins in the series at higher grade would be significantly more expensive.

Hello, that sounds like a good project! I hadn't heard of a Glan Thompson prism before, but it seems similar in concept to a Nicol prism. The Nicol prism has been on my list of projects to try out, but unfortunately I haven't yet, so I may not be as helpful with specifics. I can help you orient your calcite crystal appropriately to locate the c- and a-axes if you know at what angles to the crystallographic axes your cuts need to be made. In fact, that's worth a nerdy mineral video! As for the cutting of the calcite, I usually do this by hand using a series of glass plates and progressively finer silicon carbide grinding grit (coarse, 220, 500) with a bit of water as a lubricant to form a slurry. The hard part is polishing the calcite; there has to be a better method out there than the one I use. Currently I use a felt bob charged with white rouge polishing compound with a rotary tool, but this needs to be done carefully for both safety and effectiveness. Because calcite is so soft/prone to cleavage/prone to mechanical twinning it gets treated differently than pretty much every other mineral that I've worked with. Let me know if you think a calcite orientation video would be useful to you, and let me know how your project goes!

@@willsnellius definitely!!! I have been scouring the web and youtube videos sources and no luck so yes it would definitely be a cool video! Since i want to shine a laser through the crystal I am thinking the the facets should be smooth finish and flat as possible. For some reason I keep thinking of a flat glass plate (or similar) with a fine polishing compound charged on the surface and a steady hand so to speak. I have a tile cutter but need to purchase a thinner diamond impregnated disc of steel for this to work better. I tried cutting a calcite crystal and it started to cut but because it is so thick it grabbed the crystal and cleaved the crystal into smaller fragments etc. I still have some nice pieces but i need to figure out the orientation to polish the right faces for the extraordinary and ordinary light emissions etc.

Sounds good. I've got one more video in process to finish up first, but then I'll work on a video to explain how to orient a calcite rhombohedron. I haven't had any success in trying to use either a saw or lap when working with calcite; both ended with cleavage fragments or unwanted subsurface damage. Also the polishing technique with the felt bob charged with white rouge doesn't produce the flattest facets, so that may need to be improved. Good luck and let me know if you find those calcite cutting angles or better calcite cutting/polishing methods!

@@georgeyork8975 here's a video on how to orient calcite crystallographically. Let me know if this is helpful. czcams.com/video/nGVxzcjvW1s/video.html

@@willsnellius Ill check it our and let you know thanks!!!!!!

The George III pennies are pretty awesome. Since the 1797 pennies were 1 ounce and the 1797 two pence were 2 ounces they were also used as standard weights for commerce. I imagine that's part of the reason they ended up in such rough shape!

@@willsnellius Also being made of Copper didn't help. Post 1859 production of pennies was of bronze.