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Cerussite

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Mineral(s): Cerussite, minor Duftite
Locality: Tsumeb Mine, Tsumeb, Otjikoto Region, Namibia
Specimen size: 6.2 x 4.1 x 6.2 cm

This is a gigantic single crystal of the heavy lead carbonate mineral cerussite, with a smaller crystal growing off to the side and a coating of green duftite towards the base. The specimen comes from one of the most famous mineral localities in the world, Tsumeb, Namibia. The locality has produced some of the best cerussite crystals ever found, and I think only rivals cerussite crystals from Morocco.

Cerussite is an interesting mineral in that its crystals are often found in twinned habits, such as reticulated and cyclic twinning where crystals grow in a snowflake-like formation. In addition to its crystals being very heavy, cerussite also has a very high index of refraction close to that of a diamond, and also has a degree of light dispersion (a.k.a. "fire" or color play) that is higher than that of a diamond. What this means is that rays of light are easily split and bounces off of the crystal surface like crazy. The result of a high index of refraction means that there is a lot of sparkle if cerussite is cut into a gemstone, where light can bounce off of the many facets/crystal faces. And the result of a high degree of light dispersion means that those sparkles will be very colorful and rainbow-like. Cerussite's softness and lead content makes it unsuitable for jewelry, but it WILL shine brighter than any diamond you'll ever see if it is cut. I know of at least two cut gemstones that were for sale at the main Tucson gem and mineral show this year (2019), and the prices were around $12,000-14,000.
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© 2019 - 2021 bmah
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rosiecrafts's avatar
yes, thank you for the information!:) (Smile) awesome!
bmah's avatar
Thanks! I’ve noticed you complemented on a couple of my photos, but you haven’t really said anything specific. What’s your favorite mineral and why? I’m always interested. :)
rosiecrafts's avatar
My favorite is amethyst because my favorite color is purple and it's pretty!Amethyst Pixel Gem 
Schmiegel's avatar
Thank you for the great info!
Maybe a reason for the extra fire compared to a diamond is the strong double refraction of the crystal (as it can be seen in your great photo at the top of the crystal). Diamond as a cubic crystal doesn't have double refraction.
Some gorgeous Cerussite crystals are grown as heart shaped twins - these are my favourites! :)

Here I found a few that almost make me drool ;)

insta-stalker.com/tag/Cerussit…
 
And at the end - it's note nice to link to own images in a comment - but I once tried to catch the fire in a stereo shot here: 3d 3d 3d 
Didn't catch the fire successfully but it also shows the double refraction nicely.
bmah's avatar
I’ve edited my description because I think the more correct term for fire or color play is light dispersion. If light dispersion is the difference between the index of refraction of the purple wavelength and that of the red wavelength, then that means cerussite has a greater difference between those two ends of the spectrum. I’m sure a combination of elements involved and the crystal lattice is responsible for that. Yes, good eye on that “phantom” you see on the main crystal!

I know of those Instagram photos and videos well...there are some truly stunning examples out there. You probably noticed a well-photographed heart-shaped cerussite V-twin; that specimen belongs to a friend of mine’s. Wish I could see that one in person!

I think it’s fine to link your own image! Nice attempt on that stereoscopic image. The fire in cerussite isn’t always present or easy to see in any given specimen, because I think the crystals need to have numerous internal cleavages or crystal faces to have the light bounce and split apart. Videos show fire way better than photos can in my opinion.
Schmiegel's avatar
Thank you - didn't find a nice video yet but I'm not in Instagram.
What I noticed is that nice twins aren't sold anymore on the Munich trade show for years. So I value mine more and more :)
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