Jump to content

Recommended Posts

Two highly polished, end cut Stromatolite agate achats from the Mátra mountains, Gyöngyöstarján, Hungary  from the Miocene, 20 million years ago that I recently purchased.  These are the first Stromatolite fossils that I’ve added to my fossil collection.  I’m posting a few pictures to show the incredible colors in these pieces.

 

End Cut (1) ( 543grams 103mm by 102mm by 35mm)

 

 

1957445500_2PolishedStromatoliteAgateAchatFromMtramountainsGyngystarjnHungary20millionyearsago-EndCut-543g103x102x35mm2a1.thumb.jpg.069e0f96d55c73d34219ff37a4f2b040.jpg

 

1102176647_2PolishedStromatoliteAgateAchatFromMtramountainsGyngystarjnHungary20millionyearsago-EndCut-543g103x102x35mm2c.thumb.jpg.096c4aeeda2dd32682ca860f467361e2.jpg

 

1526578943_2PolishedStromatoliteAgateAchatFromMtramountainsGyngystarjnHungary20millionyearsago-EndCut-543g103x102x35mm2a3.thumb.jpg.7234aa196acc39e941298d9d36b23154.jpg

 

1326097449_2PolishedStromatoliteAgateAchatFromMtramountainsGyngystarjnHungary20millionyearsago-EndCut-543g103x102x35mm2a4.thumb.jpg.61bf298298570e9f0d5499ce81d0d6ac.jpg

 

1941530861_2PolishedStromatoliteAgateAchatFromMtramountainsGyngystarjnHungary20millionyearsago-EndCut-543g103x102x35mm2a5.thumb.jpg.4ad9f82fa9a70dc5ec2a26b4b0b07670.jpg

 

1154665282_2PolishedStromatoliteAgateAchatFromMtramountainsGyngystarjnHungary20millionyearsago-EndCut-543g103x102x35mm2a6.thumb.jpg.d1f1d98c373ce0f174253bb4eafdf7ea.jpg

 

59117981_2PolishedStromatoliteAgateAchatFromMtramountainsGyngystarjnHungary20millionyearsago-EndCut-543g103x102x35mm2a7.thumb.jpg.78df9e9e64196b14818e2620657e68c5.jpg

 

1868425661_2PolishedStromatoliteAgateAchatFromMtramountainsGyngystarjnHungary20millionyearsago-EndCut-543g103x102x35mm2a8.thumb.jpg.32c7f875e7a6aba4e1f0cab4d3a2b2f1.jpg

 

 

End Cut 2 (166grams 75mm by 45mm by 45mm)

 

 

860949329_1PolishedStromatoliteAgateAchatFromMtramountainsGyngystarjnHungary20millionyearsago-EndCut-166g75x45x45mm1a.thumb.jpg.66e54a2e51aac9a8c9c00887128efc4b.jpg

 

1234390448_1PolishedStromatoliteAgateAchatFromMtramountainsGyngystarjnHungary20millionyearsago-EndCut-166g75x45x45mm1c.thumb.jpg.d9cffc328d5c7ce9f448e74f7b345274.jpg

 

1840341936_1PolishedStromatoliteAgateAchatFromMtramountainsGyngystarjnHungary20millionyearsago-EndCut-166g75x45x45mm1a2.thumb.jpg.e7f1e23a3eff52bb877e30840cd26a05.jpg

 

411787294_1PolishedStromatoliteAgateAchatFromMtramountainsGyngystarjnHungary20millionyearsago-EndCut-166g75x45x45mm1a3.thumb.jpg.c95ae24298a206f56ffb0519debd2899.jpg

 

1861319681_1PolishedStromatoliteAgateAchatFromMtramountainsGyngystarjnHungary20millionyearsago-EndCut-166g75x45x45mm1a4.thumb.jpg.8238f40aaff7fe629bf9c49c95632e71.jpg

 

581322421_1PolishedStromatoliteAgateAchatFromMtramountainsGyngystarjnHungary20millionyearsago-EndCut-166g75x45x45mm1a5.thumb.jpg.9707484690a84689ec815d64962d2588.jpg

 

794122774_1PolishedStromatoliteAgateAchatFromMtramountainsGyngystarjnHungary20millionyearsago-EndCut-166g75x45x45mm1a6.thumb.jpg.648c5dc845666ffcb03a315679c10882.jpg

 

2095398617_1PolishedStromatoliteAgateAchatFromMtramountainsGyngystarjnHungary20millionyearsago-EndCut-166g75x45x45mm1a7.thumb.jpg.82c454485bdf8ecbd81b39ec85ba1a52.jpg

 

 

Marco Sr.

  • Enjoyed 5

"Any day that you can fossil hunt is a great day."

My family fossil website     Some Of My Shark, Ray, Fish And Other Micros     My Extant Shark Jaw Collection

image.png.9a941d70fb26446297dbc9dae7bae7ed.png image.png.41c8380882dac648c6131b5bc1377249.png

Link to comment
Share on other sites

Interesting (and beautiful). I've never seen silicified stromatolites like this before. Looks like a lot of the normal layered structure has been reworked during the mineralization process. This reminds me of the Withlacoochee silicified corals where the polyp structure of the coral is faint or lost completely during the transformation from calcium carbonate to chalcedony.

 

Some of the images above remind me of Hubble imagery of deep space features like the Crab Nebula. :)

 

 

Cheers.

 

-Ken

Link to comment
Share on other sites

1 hour ago, digit said:

Interesting (and beautiful). I've never seen silicified stromatolites like this before. Looks like a lot of the normal layered structure has been reworked during the mineralization process. This reminds me of the Withlacoochee silicified corals where the polyp structure of the coral is faint or lost completely during the transformation from calcium carbonate to chalcedony.

 

Some of the images above remind me of Hubble imagery of deep space features like the Crab Nebula. :)

 

 

Cheers.

 

-Ken

 

The vivid colors in these specimens are incredible.  According to the seller, the most common bacteria are Gallionella Ferruginea and Leptothrix Ochrea which can appear as tubular stringy fibers, plume-like inclusions and cauliflower-like stromolytics in the agate.

 

Marco Sr.

  • I found this Informative 1

"Any day that you can fossil hunt is a great day."

My family fossil website     Some Of My Shark, Ray, Fish And Other Micros     My Extant Shark Jaw Collection

image.png.9a941d70fb26446297dbc9dae7bae7ed.png image.png.41c8380882dac648c6131b5bc1377249.png

Link to comment
Share on other sites

e.g.:

JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 113, B08S05, doi:10.1029/2007JB005482, 2008

Mineralized microbes from Giggenbach submarine volcano
Brian Jones, C. E. J. de Ronde, and Robin W. Renaut

includes descriptions of morphotypes,remarks on the diagenesis and/or taphonomy

Jones and Renaut have written extensively on siliceous sinters of various kinds

 

2007JB005482.pdf

afbeelding_2021-02-19_174659.png

  • I found this Informative 2

 

 

 

Link to comment
Share on other sites

If you ever get tired of them, or don't have room for them, let me know.  :D But seriously.. those are really beautiful. 

  • Thank You 1

Accomplishing the impossible means only that the boss will add it to your regular duties.

Link to comment
Share on other sites

4 hours ago, doushantuo said:

e.g.:

JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 113, B08S05, doi:10.1029/2007JB005482, 2008

Mineralized microbes from Giggenbach submarine volcano
Brian Jones, C. E. J. de Ronde, and Robin W. Renaut

includes descriptions of morphotypes,remarks on the diagenesis and/or taphonomy

Jones and Renaut have written extensively on siliceous sinters of various kinds

 

2007JB005482.pdf 965.37 kB · 2 downloads

 

 

Really interesting paper.  Thank you for posting.

 

Marco Sr.

"Any day that you can fossil hunt is a great day."

My family fossil website     Some Of My Shark, Ray, Fish And Other Micros     My Extant Shark Jaw Collection

image.png.9a941d70fb26446297dbc9dae7bae7ed.png image.png.41c8380882dac648c6131b5bc1377249.png

Link to comment
Share on other sites

Wow, those are some VERY colorful stromatolites. I've found ones that are varying shades of gray/blue, green, and pink, but nothing as colorful as these.

  • Thank You 1
Link to comment
Share on other sites

17 hours ago, Allosaurus said:

Wow, those are some VERY colorful stromatolites. I've found ones that are varying shades of gray/blue, green, and pink, but nothing as colorful as these.

 

These end-cuts from Hungary contain the most colorful stromatolites that I've seen.  However, Mary Ellen Jasper from Minnesota can have vivid red stromatolites on a black background which are awesome.  Apple Valley Jasper from Morocco can also have very colorful stromatolites.  I have a few Mary Ellen Jasper pieces in the mail right now.  I'm looking for a few nice pieces of Apple Valley Jasper but everything I see is very expensive or not a nice slab or end-cut.

 

Marco Sr.

"Any day that you can fossil hunt is a great day."

My family fossil website     Some Of My Shark, Ray, Fish And Other Micros     My Extant Shark Jaw Collection

image.png.9a941d70fb26446297dbc9dae7bae7ed.png image.png.41c8380882dac648c6131b5bc1377249.png

Link to comment
Share on other sites

  • 2 weeks later...

Below is a Mary Ellen Jasper slab (222grams 135mm x 90mm x 5to 9mm thick) with stromatolites from near Biwabik, central St. Louis County, northeastern Minnesota, USA from the Biwabik Iron Formation (upper Paleoproterozoic >1.85 billion years).

 

The convex-upward, layered, red columnal structures in the slab shown below are the stromatolites.  Stromatolites are built up by mats of cyanobacteria typically living in very shallow marine settings.  The layering of stromatolites is principally the result of tidally rhythmic deposition of sediments atop the cyanobacterial mats.

 

Because cyanobacteria are photosynthetic and want to face the sun, it is believed that the sinuosity of the stromatolite columns is the result of tracking of the sun over many seasons.

 

1717125564_8MaryEllenJasperslabKelleysKaleidoscope222g135mm90mm5to9mmthick1.thumb.jpeg.682ed328ecf7cef24e831e1f94d5e8e7.jpeg

 

1631237840_8MaryEllenJasperslabKelleysKaleidoscope222g135mm90mm5to9mmthick2.thumb.jpeg.7b76eed3d2a05f3bd6170b55290dab32.jpeg

 

1029377514_8MaryEllenJasperslabKelleysKaleidoscope222g135mm90mm5to9mmthick2a1.thumb.jpg.6e5b1582d4f145f7b5d3ea8d43df8e12.jpg

 

373625434_8MaryEllenJasperslabKelleysKaleidoscope222g135mm90mm5to9mmthick2a2.thumb.jpg.f3f9118199e31a1b7eba5f07f397dbe7.jpg

 

1248098229_8MaryEllenJasperslabKelleysKaleidoscope222g135mm90mm5to9mmthick2a3.thumb.jpg.ecb6a50002e2ee6103f92e0464a659f1.jpg

 

1963249741_8MaryEllenJasperslabKelleysKaleidoscope222g135mm90mm5to9mmthick2a5.thumb.jpg.3f241dd27eba16240adbb0bfa4660754.jpg

 

82643896_8MaryEllenJasperslabKelleysKaleidoscope222g135mm90mm5to9mmthick2a9.thumb.jpg.f46a737ae26cf9b6b71f0e70b9301a43.jpg

 

109008120_8MaryEllenJasperslabKelleysKaleidoscope222g135mm90mm5to9mmthick2a10.thumb.jpg.5b03523fcf1d2ee305e6c87916135e75.jpg

 

Marco Sr.

  • I found this Informative 1
  • Enjoyed 3

"Any day that you can fossil hunt is a great day."

My family fossil website     Some Of My Shark, Ray, Fish And Other Micros     My Extant Shark Jaw Collection

image.png.9a941d70fb26446297dbc9dae7bae7ed.png image.png.41c8380882dac648c6131b5bc1377249.png

Link to comment
Share on other sites

Another highly polished, end cut Stromatolite agate achat from the Mátra mountains, Gyöngyöstarján, Hungary  from the Miocene, 20 million years ago that I recently purchased.

 

End cut (78grams 69mm x 45mm x 17mm thick)

 

 

1467846084_TFF7PolishedStromatoliteAgateAchatFromMtramountainsGyngystarjnHungary20millionyearsago-EndCut-78g69x45x17mma.jpg.bdc81e31bfd12ad64086222298cde088.jpg

 

2132962968_TFF7PolishedStromatoliteAgateAchatFromMtramountainsGyngystarjnHungary20millionyearsago-EndCut-78g69x45x17mmb.jpg.0e8620277fc2e5a2154ba2da645a7c6b.jpg

 

1142954606_TFF7PolishedStromatoliteAgateAchatFromMtramountainsGyngystarjnHungary20millionyearsago-EndCut-78g69x45x17mma1.jpg.6574c8252e66e73630227ff817322e52.jpg

 

2057222827_TFF7PolishedStromatoliteAgateAchatFromMtramountainsGyngystarjnHungary20millionyearsago-EndCut-78g69x45x17mma2.jpg.9a6f2c87246163dcf73b57caba17cd71.jpg

 

1330543720_TFF7PolishedStromatoliteAgateAchatFromMtramountainsGyngystarjnHungary20millionyearsago-EndCut-78g69x45x17mma3.jpg.d2e51221a19e324900f2ab64d1c32300.jpg

 

1908544456_TFF7PolishedStromatoliteAgateAchatFromMtramountainsGyngystarjnHungary20millionyearsago-EndCut-78g69x45x17mma4.jpg.24d18d11438701de0d44a4385e986a41.jpg

 

147279821_TFF7PolishedStromatoliteAgateAchatFromMtramountainsGyngystarjnHungary20millionyearsago-EndCut-78g69x45x17mma5.jpg.cf7da2117367af3cf3139fff6632286e.jpg

 

 

Marco Sr.

  • Enjoyed 3

"Any day that you can fossil hunt is a great day."

My family fossil website     Some Of My Shark, Ray, Fish And Other Micros     My Extant Shark Jaw Collection

image.png.9a941d70fb26446297dbc9dae7bae7ed.png image.png.41c8380882dac648c6131b5bc1377249.png

Link to comment
Share on other sites

  • 2 weeks later...

A slab (10" x 6" x .27" weight 24 oz.) of 3.02 billion-year-old tiger iron collected from the Ord Ranges in Western Australia.  Tiger Iron is a banded structure of Tigers Eye, Red Jasper, and Hematite. One theory is that tiger iron is a typical stromatolite that has undergone mineral replacement with iron oxide. Another is that the microbes formed the banded iron directly while the stromatolite was being formed. Yet another is that it was formed indirectly by stromatolites when the oxygen they produced mixed with iron produced by submarine volcanoes precipitating bands of iron oxide (from seller's posting).

 

 

650940929_TFF10TigerIronslabAustralia10X6X.27inches24oz1.jpg.952509b7be8c42c742e2e62977fa1e67.jpg

 

1145034113_TFF10TigerIronslabAustralia10X6X.27inches24oz2.jpg.a212ffafa355dc93cd4974f6c4415015.jpg

 

867525060_10TigerIronslabAustralia10X6X.27inches24oz3.thumb.jpg.0846939263cac22796180b7b8bb5755a.jpg

 

1216606859_10TigerIronslabAustralia10X6X.27inches24oz4.thumb.jpg.af1de6408eed9c6c30450e5404421f65.jpg

 

930502414_10TigerIronslabAustralia10X6X.27inches24oz5.thumb.jpg.375e9e3566056471c517b7ef5ef476a2.jpg

 

920904884_10TigerIronslabAustralia10X6X.27inches24oz6.thumb.jpg.50322c061a8366faf6db2fbb42dd72d5.jpg

 

225747035_10TigerIronslabAustralia10X6X.27inches24oz7.thumb.jpg.2e55a4d78d34f9811649730ed61eef8e.jpg

 

1497653104_10TigerIronslabAustralia10X6X.27inches24oz8.thumb.jpg.0c8f39218995b1c34614f06abbf77b22.jpg

 

1880149018_10TigerIronslabAustralia10X6X.27inches24oz9.thumb.jpg.dd36f46656381169acfe624bca1e725c.jpg

 

60992812_10TigerIronslabAustralia10X6X.27inches24oz11.thumb.jpg.65c44279fbd60672f39416f66fc0d5d7.jpg

 

 

 

Marco Sr.

  • Enjoyed 2

"Any day that you can fossil hunt is a great day."

My family fossil website     Some Of My Shark, Ray, Fish And Other Micros     My Extant Shark Jaw Collection

image.png.9a941d70fb26446297dbc9dae7bae7ed.png image.png.41c8380882dac648c6131b5bc1377249.png

Link to comment
Share on other sites

Last slab is beautiful, though I'd have to say that slab is more likely Marra Mamba Tiger Eye vs Tiger Iron. Tiger Iron is usually darker & more layered.

Top is Marra Mamba Tiger Eye, the other 3 are tiger Iron. People interchange the names Tiger Eye/Iron so frequent without knowing, then you have the South Africa version of Tiger Eye/Iron (both) that look similar though slightly different than the Australia versions.

Last one is Tiger Iron from South Africa

 

 

1.jpeg

5.jpeg

6.jpeg

43.jpeg

195.jpeg

Edited by Abyss
  • Enjoyed 1
Link to comment
Share on other sites

6 hours ago, Abyss said:

Last slab is beautiful, though I'd have to say that slab is more likely Mara Mamba Tiger Eye vs Tiger Iron. Tiger Iron is usually darker & more layered.

Top is Marra Mamba Tiger Eye, the other 3 are tiger Iron. People interchange the names Tiger Eye/Iron so frequent without knowing, then you have the South Africa version of Tiger Eye/Iron (both) that look similar though slightly different than the Australia versions.

Last one is Tiger Iron from South Africa

 

 

1.jpeg

 

 

43.jpeg

 

 

It is very difficult to get data on a lot of slabs from on-line sellers because they bought the slabs from estate sales or rock shops that closed and the sellers have little data on them.  I actually questioned the seller on this slab, because as you point out, it really doesn't look like the tiger iron images on-line.  The seller bought it at an estate sale and claimed it was identified as tiger iron from Australia.  However, to me, it does look more like Mara Mamba Tiger Eye from Australia which is much rarer.  However, my camera flash may have altered the slab colors in the slab pictures that I posted above to make the slab colors brighter and the pictures misleading.  Below is one of the seller's slab pictures which show darker colors.  However, the slab colors in natural light look closer to the colors in your posted picture of Mara Mamba Tiger Eye than the colors in either my pictures or the seller's pictures.

 

 

1952704349_TigerIronslabAustralia3.thumb.jpg.88cae594a9cce0f8067ba48aacbdd0b7.jpg

 

 

Marco Sr.

  • Enjoyed 1

"Any day that you can fossil hunt is a great day."

My family fossil website     Some Of My Shark, Ray, Fish And Other Micros     My Extant Shark Jaw Collection

image.png.9a941d70fb26446297dbc9dae7bae7ed.png image.png.41c8380882dac648c6131b5bc1377249.png

Link to comment
Share on other sites

  • 1 month later...

I was hesitant to buy a Malachite slab because there is disagreement on whether Malachite is a Stromatolite.  In Leis, Stinchcomb, Mckee, 2015, Stromatolites Ancient, Beautiful, and Earth-Altering, the author calls it a “dubiostromatolite” but states “Some could be a stromatolite in that they might have had a biogenic origin and be made by copper oxidizing chemoautotrophs."  Other authors believe that Malachite is definitely a stromatolite.  However, the below slab, although smaller than some other slabs for sale, had an incredible set of patterns that I just couldn’t pass up.

 

Malachite slab, 900 Million Yrs. Old, Precambrian Neoproterozoic, Katanga formation, Tantara Mine, Congo, Africa, 474 grams or 1 lb., 5” x 3.5” x .5”:

 

1133427125_51Malachite97.56USD900MillionYrs.OldPrecambrianNeoproterozoicKatangaformationTantaraMineCongoAfrica474gor1lb5x3_5x.5inches1.jpg.138f9b4b292654ba565d6822b7d7e9fb.jpg

 

1377421452_51Malachite97.56USD900MillionYrs.OldPrecambrianNeoproterozoicKatangaformationTantaraMineCongoAfrica474gor1lb5x3_5x.5inches2.thumb.jpg.a4fda44d53b0142e28c5764abc9e52ba.jpg

 

757377176_51Malachite97.56USD900MillionYrs.OldPrecambrianNeoproterozoicKatangaformationTantaraMineCongoAfrica474gor1lb5x3_5x.5inches3.thumb.jpg.be96756db94b4fd47910ea39f506da31.jpg

 

372612014_51Malachite97.56USD900MillionYrs.OldPrecambrianNeoproterozoicKatangaformationTantaraMineCongoAfrica474gor1lb5x3_5x.5inches4.thumb.jpg.5f81575155541670f42f877da4a84c4b.jpg

 

705875356_51Malachite97.56USD900MillionYrs.OldPrecambrianNeoproterozoicKatangaformationTantaraMineCongoAfrica474gor1lb5x3_5x.5inches5.thumb.jpg.d0124fb5260c6b66aa9133b437a8b69d.jpg

 

1069169495_51Malachite97.56USD900MillionYrs.OldPrecambrianNeoproterozoicKatangaformationTantaraMineCongoAfrica474gor1lb5x3_5x.5inches6.thumb.jpg.a19303f2d6dcce8eded92ed357c1ce23.jpg

 

1735990502_51Malachite97.56USD900MillionYrs.OldPrecambrianNeoproterozoicKatangaformationTantaraMineCongoAfrica474gor1lb5x3_5x.5inches7.thumb.jpg.0eedcf4f2f3c558b155ff112f232a81c.jpg

 

917427860_51Malachite97.56USD900MillionYrs.OldPrecambrianNeoproterozoicKatangaformationTantaraMineCongoAfrica474gor1lb5x3_5x.5inches8.thumb.jpg.6320c70dcb7755a1a3c2926536b5aa90.jpg

 

166930969_51Malachite97.56USD900MillionYrs.OldPrecambrianNeoproterozoicKatangaformationTantaraMineCongoAfrica474gor1lb5x3_5x.5inches9.thumb.jpg.70a51d26813bd4e9e1af8192a894806b.jpg

 

959872571_51Malachite97.56USD900MillionYrs.OldPrecambrianNeoproterozoicKatangaformationTantaraMineCongoAfrica474gor1lb5x3_5x.5inches10.thumb.jpg.aa9bba81d0bf9d0abd85c8ae606a9efc.jpg

 

 

Marco Sr.

  • Enjoyed 2

"Any day that you can fossil hunt is a great day."

My family fossil website     Some Of My Shark, Ray, Fish And Other Micros     My Extant Shark Jaw Collection

image.png.9a941d70fb26446297dbc9dae7bae7ed.png image.png.41c8380882dac648c6131b5bc1377249.png

Link to comment
Share on other sites

@MarcoSr

 

The malachite slab is fantastic.

 

I have seen rough fibrous malachite offered online.

Is that different to the polished slabs?? 

MOTM.png.61350469b02f439fd4d5d77c2c69da85.png.a47e14d65deb3f8b242019b3a81d8160.png MotM August 2023 - Eclectic Collector

Link to comment
Share on other sites

On 3/6/2021 at 5:02 AM, MarcoSr said:

Below is a Mary Ellen Jasper slab ...

1717125564_8MaryEllenJasperslabKelleysKaleidoscope222g135mm90mm5to9mmthick1.thumb.jpeg.682ed328ecf7cef24e831e1f94d5e8e7.jpeg

 

 

You're getting some nice pieces of everything, Marco. I don't know how you do it, though I suspect money is involved...  Somehow I missed this one when you first posted it. I have 8 pieces of MEJ and none of them are quite as good.

 

  • Enjoyed 1
Link to comment
Share on other sites

49 minutes ago, Yoda said:

@MarcoSr

The malachite slab is fantastic.

I have seen rough fibrous malachite offered online.

Is that different to the polished slabs?? 

It's the same mineral, just different growth patterns.

I doubt malachite is biogenic but that slab has me doubting myself.... seeing similarities to the Cotham marble. But usually the concentric layering-type growth looks the same as the travertine you see from caves. Chances of that being biogenic can't be any greater than the Isua stuff or the Tiger Iron above, could they?

  • I found this Informative 1
Link to comment
Share on other sites

On 4/24/2021 at 2:24 PM, MarcoSr said:

Malachite slab, 900 Million Yrs. Old, Precambrian Neoproterozoic, Katanga formation

Very nice - and very unusual for Katanga malachite!

Color is completely off for malachite, sure it is really malachite and not something different with copper impurities (either as solid solution of as mineral inclusions)?

And more general, isn´t all that malachite in that area supergene in origin, formed long after the primary copper ore has formed? Well, this does not exclude biological involvement.

Franz Bernhard

  • I found this Informative 1
Link to comment
Share on other sites

6 hours ago, Wrangellian said:

 

You're getting some nice pieces of everything, Marco. I don't know how you do it, though I suspect money is involved...  Somehow I missed this one when you first posted it. I have 8 pieces of MEJ and none of them are quite as good.

 

 

Actually I spend a lot of time on the web at night when I can't sleep and keep an eye out for special pieces at reasonable prices.  I bought it rough and hand sanded it.  Although it only took about an hour to go through the different grits, I definitely prefer to buy the slabs already polished.

 

Marco Sr.

"Any day that you can fossil hunt is a great day."

My family fossil website     Some Of My Shark, Ray, Fish And Other Micros     My Extant Shark Jaw Collection

image.png.9a941d70fb26446297dbc9dae7bae7ed.png image.png.41c8380882dac648c6131b5bc1377249.png

Link to comment
Share on other sites

2 hours ago, Wrangellian said:

It's the same mineral, just different growth patterns.

I doubt malachite is biogenic but that slab has me doubting myself.... seeing similarities to the Cotham marble. But usually the concentric layering-type growth looks the same as the travertine you see from caves. Chances of that being biogenic can't be any greater than the Isua stuff or the Tiger Iron above, could they?

 

2 hours ago, FranzBernhard said:

Very nice - and very unusual for Katanga malachite!

Color is completely off for malachite, sure it is really malachite and not something different with copper impurities (either as solid solution of as mineral inclusions)?

And more general, isn´t all that malachite in that area supergene in origin, formed long after the primary copper ore has formed? Well, this does not exclude biological involvement.

Franz Bernhard

 

I'm not convinced that this piece is biogenic, but I just couldn't pass it up because of the patterns.  I've looked at hundreds of Malachite pieces on the web and this one piece seemed somewhat unique.  The seller of this piece had lots of other Malachite pieces for sale and specifically told me that the piece came from the Katanga formation, Tantara Mine, Congo, Africa after I specifically asked in a message.   I've noticed with a number of different pieces from different famous mines that you can get variation in color and a real variation in the patterns,  I'm assuming it because the pieces came from a different area in the mine that had slightly different forming conditions.  I'm waiting on some Kona Dolomite pieces that all have different patterns (laminar, wavy, digitate, oncolite etc.) and colors and the pieces are all from the same general area.  Some of these pieces look totally different than most of the Kona Dolomite pieces on the web.

 

Marco Sr.

 

"Any day that you can fossil hunt is a great day."

My family fossil website     Some Of My Shark, Ray, Fish And Other Micros     My Extant Shark Jaw Collection

image.png.9a941d70fb26446297dbc9dae7bae7ed.png image.png.41c8380882dac648c6131b5bc1377249.png

Link to comment
Share on other sites

4 hours ago, Yoda said:

@MarcoSr

 

The malachite slab is fantastic.

 

I have seen rough fibrous malachite offered online.

Is that different to the polished slabs?? 

 

3 hours ago, Wrangellian said:

It's the same mineral, just different growth patterns.

I doubt malachite is biogenic but that slab has me doubting myself.... seeing similarities to the Cotham marble. But usually the concentric layering-type growth looks the same as the travertine you see from caves. Chances of that being biogenic can't be any greater than the Isua stuff or the Tiger Iron above, could they?

 

As Wrangellian said, the same mineral, just different growth patterns.  A lot of the Malachite pieces on the web are polished to really bring out the patterns.  The fibrous malachite tends to be rough or unpolished.

 

Marco Sr.

  • I found this Informative 1

"Any day that you can fossil hunt is a great day."

My family fossil website     Some Of My Shark, Ray, Fish And Other Micros     My Extant Shark Jaw Collection

image.png.9a941d70fb26446297dbc9dae7bae7ed.png image.png.41c8380882dac648c6131b5bc1377249.png

Link to comment
Share on other sites

3 hours ago, MarcoSr said:

 

Actually I spend a lot of time on the web at night when I can't sleep and keep an eye out for special pieces at reasonable prices.  I bought it rough and hand sanded it.  Although it only took about an hour to go through the different grits, I definitely prefer to buy the slabs already polished.

Marco Sr.

Well it seems like you got a decent deal on it. You're not the only one who spends time in the wee hours looking for things, but somehow a lot of stuff passes me by..

Good when you are able to buy your own rough or rough slabbed, and cut/finish it yourself, if it saves money. I've got a number of slices of various things that I need to get polished. I already have a saw but need to be able to polish stuff. Planning to go to our rockhound club workshop for this when things open up again, but on the other hand I found out I've actually got a flat lap, just need to get it set up and maybe I'll finally be able to do that part too! (Seems like a lot more work doing the polishing by hand :oO: )

Link to comment
Share on other sites

1 hour ago, Wrangellian said:

Well it seems like you got a decent deal on it. You're not the only one who spends time in the wee hours looking for things, but somehow a lot of stuff passes me by..

Good when you are able to buy your own rough or rough slabbed, and cut/finish it yourself, if it saves money. I've got a number of slices of various things that I need to get polished. I already have a saw but need to be able to polish stuff. Planning to go to our rockhound club workshop for this when things open up again, but on the other hand I found out I've actually got a flat lap, just need to get it set up and maybe I'll finally be able to do that part too! (Seems like a lot more work doing the polishing by hand :oO: )

 

It is a lot of work to polish by hand.  I don't do any cutting and will only polish by hand a small special piece.

 

Marco Sr.

 

"Any day that you can fossil hunt is a great day."

My family fossil website     Some Of My Shark, Ray, Fish And Other Micros     My Extant Shark Jaw Collection

image.png.9a941d70fb26446297dbc9dae7bae7ed.png image.png.41c8380882dac648c6131b5bc1377249.png

Link to comment
Share on other sites

13 hours ago, MarcoSr said:

I'm waiting on some Kona Dolomite pieces that all have different patterns (laminar, wavy, digitate, oncolite etc.) and colors and the pieces are all from the same general area.  Some of these pieces look totally different than most of the Kona Dolomite pieces on the web.

 

Marco Sr.

 

 

@FranzBernhard @Wrangellian

Here are the examples that I was talking about with the Kona Dolomite showing different colors and patterns.  These pieces are being sent right now, so I have to use the pictures of the seller.  Following is a message from the seller that discusses the location.

 

"Yes, all my Kona is basically from one location. The “blah” pink Kona has been grossly overdone by lapidary folks and the really neat stromatolites mostly overlooked. There are dozens of small subunits each of which present a unique view into this shallow marine stromatolite environment. The age has been most recently and accurately refined to 2.2 to 2.3 Billion based on specific units of interest. We will stick with our original assessment of 2.2 to 2.4 Billion to cover the lowest element of the Kona. Ignore all the other ages presented on the internet. Most all of my specimens come from the Lindberg and Sons Quarry outside of Ishpeming, Michigan. Made friends with the quarry manager years ago, and he allowed me unlimited access to restricted areas of the quarry, allowed me to take advantage of some of the rarest material to be found. Also, the beds hit the surface at about 35 degrees which actually allows for more depth of the entire start column to be exposed rather than just usual horizontal beds."

 

Kona Dolomite 1 laminar 6.5 X 7 inches

 

 

image.png.07b5a6f5a9277282a8880c77cc8d164e.png

 

 

Kona Dolomite 2 snow drift layer 9x6.5 inches

 

 

image.png.f35795c1611aba375b74174976778565.png

 

 

Kona Dolomite 3 digitate 9x8 inches

 

 

image.png.b916c915a8e0ff17a3b0b4255a3263f7.png

 

 

Kona Dolomite 4 oncolites 7x3.5 inches

 

 

image.png.f912933c06bd73310ce1e171c1c88e06.png

 

 

Kona Dolomite 5 oncolites and wavy 10.5 inches

 

 

image.png.83b60978a2338289c217d1a10610faa0.png

 

 

Kona Dolomite 7 moose blood (thrombolites) 8.5 X 6 inches

 

 

image.png.cd556d4b51027cc8bff52b91c3dc76c0.png

 

Kona Dolomite 8 lace 7.5x4 inches

 

 

image.png.cf1951284c75767f40676d49f4f54bcf.png

 

 

 

 

Marco Sr.

  • I found this Informative 2
  • Enjoyed 1

"Any day that you can fossil hunt is a great day."

My family fossil website     Some Of My Shark, Ray, Fish And Other Micros     My Extant Shark Jaw Collection

image.png.9a941d70fb26446297dbc9dae7bae7ed.png image.png.41c8380882dac648c6131b5bc1377249.png

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...