Dear Andrew,
Note that the prodissoconch stage of pectinoidean molluscs is of aragonite
and that some inner layers are of crossed lamellar aragonite too.
Best wishes,
Henk
***********************************************
Henk H. Dijkstra (Hon. Res. Ass.)
c/o Zoological Museum, Dept. Malacology, University of Amsterdam
PO Box 94766, 1090 GT Amsterdam, The Netherlands
E-mail: [log in to unmask]
-----------------------------
Private address:
Gravinneweg 12, 8604 CA Sneek, The Netherlands
E-mail: [log in to unmask]
***********************************************
> Van: Andrew Grebneff <[log in to unmask]>
> Beantwoord: Conchologists of America List <[log in to unmask]>
> Datum: Tue, 29 Oct 2002 23:32:32 +1300
> Aan: [log in to unmask]
> Onderwerp: Re: habitat depletion for your health?
>
>> Dear all,
>>
>> I've just heard about "coral calcium" which is supposed to be a more
>> bio-available form of nutritional supplement.
>>
>> As an RN, I'm curious about whether there are any studies at all on this
>> claim. A cursory check only turned up many outfits selling this product.
>> There's a statement by one doctor to the effect that there's no evidence of
>> coral calcium being more beneficial--and it's on a page sponsored by a
>> business selling the conventional calcium supplement.
>>
>> On some of the product pages, there are claims that they use only
>> above-sea-level fossilized coral, which is in more bio-available (allegedly)
>> aragonite form. Other coral calcium apparently has been mined from living
>> reefs or below the reefs.
>>
>> This all sounds a little bizarre and like another threat to marine habitats.
>>
>> (Who knows, now there's robust evidence that fish oil supplements are
>> beneficial for cardiovascular health).
>>
>> David Kirsh
>> Durham, NC
>
> Aragonite is slightly less stable than calcite (most shells are
> largely composed of aragonite, though osterids, anomiids, limids,
> pectinids, propeamussiids, mytilids, isognomonids, epitoniids and
> janthinids are calcitic).
>
> But I very much doubt that either form of calcium carbonate is any
> more digestible in stomach acid than the other... and coral
> aragonite (or calcite) certainly no more so than molluscan or
> artificially-produced!
>
> It sounds like more of the moronic "organic" produce thing (when did
> you last eat an inorganic orange?).
> --
> Andrew Grebneff
> 165 Evans St, Dunedin 9001, New Zealand
> <[log in to unmask]>
> Seashell, Macintosh, VW/Toyota van nut
>
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