[Rockhounds] This 'wandering meatloaf' chiton has a rare mineral in its teeth

[Drew]

No worries, I was just clarifying that I wasn't trying to confuse the two,
just specifying what was said in the paper on the discovery from 2003.

>From my understanding, the teeth of the chiton are primarily made of
magnetite, and the santabarbaraite seems to be used in the softer parts of
the tooth structure. From the paper linked below, "the wear-resistant cusp
of the chiton radula tooth works in concert with progressively softer
microarchitectural units as the mollusk grazes on and erodes rock. Herein,
we focus on the stylus that connects the ultrahard and stiff tooth head to
the flexible radula membrane."

https://www.pnas.org/content/118/23/e2020160118

So it seems the santabarbaraite is not the main abrading material, but
rather a component of the architecture that makes the teeth more resilient.

This still doesn't answer any of the questions re: hardness, but... :)

Drew

On Sun, Jun 13, 2021 at 7:56 PM Peter Richards <rpr at heidelberg.edu> wrote:

> Sorry, Drew, if I did not understand your intention.  My criticism was
> really aimed not at you but at the authors of the quote, for making a
> meaningless statement.  I had looked up the article earlier, and it seemed
> to me to be rather full of questionable speculations.
>
> Regards,
> Pete
> ___________________________
> R. Peter Richards, Ph.D.
> rpr at heidelberg.edu
> Morphological Crystallographer
>
> > On Jun 13, 2021, at 7:32 PM, Drew <dr00bert at gmail.com> wrote:
> >
> > I was just pointing out why no hardness value could be found in
> literature.
> > Because it wasn't measured.
> >
> > There are specimens available on eBay for anyone who wants to add to the
> > literature.
> >
> > Drew
> >
> >
> >
> > On Sun, Jun 13, 2021, 19:15 Peter Richards <rpr at heidelberg.edu> wrote:
> >
> >> The density of the teeth is essentially irrelevant.  Gold has a density
> of
> >> 15 to 19, and mercury a density of 13.6.  Neither would make good
> rasping
> >> teeth.
> >>
> >> Pete Richards
> >> ___________________________
> >> R. Peter Richards, Ph.D.
> >> rpr at heidelberg.edu
> >> Morphological Crystallographer
> >>
> >>> On Jun 13, 2021, at 6:32 PM, Drew <dr00bert at gmail.com> wrote:
> >>>
> >>> "The hardness was not measured but the measured density of the type
> >>> material is 2.42 g/cm3."
> >>>
> >>>
> >>
> https://www.schweizerbart.de/papers/ejm/detail/15/54934/Santabarbaraite_a_new_amorphous_phosphate_mineral?af=crossref
> >>>
> >>> On Tue, Jun 1, 2021 at 9:37 AM THE HAMMER <hammerron at hotmail.com>
> wrote:
> >>>
> >>>> Santabarbaraite is new to me.  I did several internet searches for
> more
> >>>> information and one thing that I found odd is that I could find no
> >> mention
> >>>> to its hardness.
> >>>>
> >>>> Ron
> >>>>
> >>>>
> >>>>
> >>>> ________________________________
> >>>> From: Rockhounds <rockhounds-bounces at rockhounds.drizzle.com> on
> behalf
> >> of
> >>>> Kreigh Tomaszewski <kreigh at gmail.com>
> >>>> Sent: Monday, May 31, 2021 4:16 PM
> >>>> To: Rockhounds at drizzle.com: A mailing list for rock and gem
> collectors
> >> <
> >>>> rockhounds at rockhounds.drizzle.com>
> >>>> Subject: [Rockhounds] This 'wandering meatloaf' chiton has a rare
> >> mineral
> >>>> in its teeth
> >>>>
> >>>> A rare iron mineral has been discovered in the teeth of a living
> >> organism
> >>>> for the first time -- one that bears the pet name "wandering
> meatloaf."
> >>>> While it sounds like a tour update for the musician Meat Loaf, this
> >>>> research concerns a large mollusk called a chiton (not a "bat out of
> >>>> hell"). The mollusk, also known as Cryptochiton stelleri, got its
> >> nickname
> >>>> because it's large, reddish-brown and, well, shaped a bit like a
> >> meatloaf
> >>>> escaping the pan. It lives along rocky coastlines. The largest chiton
> in
> >>>> the world, it can reach 13 inches in length.
> >>>> Researchers were surprised to find santabarbaraite in the mollusk's
> >> tooth
> >>>> because it's previously been found only in rocks.
> >>>>
> >>>>
> >>>> Chiton need tough teeth because they essentially chew on rocks to
> scrape
> >>>> off algae and other food substances. Their teeth are one of the
> hardest
> >>>> materials in nature and are attached to a flexible tongue-like
> structure
> >>>> called a radula.
> >>>>
> >>>>
> >>
> https://www.cnn.com/2021/05/31/world/rare-mineral-chiton-mollusk-teeth-scn/index.html
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