What kind of Trochidae is it?

[paul monfils]

Many species of Trochidae and Turbinidae have mother of pearl interiors, so commercial shell outlets that supply items for tourist shops, etc. make decorative items from them by grinding or etching off the outer layers of shell until they reach the interior pearly layer, so the exterior looks pearly.  For the most part such shells are of little interest to collectors.  They are decorative only.

<a href="http://www.shellhorizons.com/details.asp?ProductID=S1-37&Page=3" target="_blank"><!-- m --><a class="postlink" href="http://www.shellhorizons.com/details.asp?ProductID=S1-37&Page=3">http://www.shellhorizons.com/details.as ... -37&Page=3</a><!-- m --></a>

<a href="http://www.shellhorizons.com/details.asp?ProductID=I1-6&Page=3" target="_blank"><!-- m --><a class="postlink" href="http://www.shellhorizons.com/details.asp?ProductID=I1-6&Page=3">http://www.shellhorizons.com/details.as ... 1-6&Page=3</a><!-- m --></a>

<a href="http://www.shellhorizons.com/details.asp?ProductID=E3-17&Page=4" target="_blank"><!-- m --><a class="postlink" href="http://www.shellhorizons.com/details.asp?ProductID=E3-17&Page=4">http://www.shellhorizons.com/details.as ... -17&Page=4</a><!-- m --></a>

There is one species of Trochidae in which the outer shell layer is so thin that the inner pearl layer actually shows through, and in some specimens the thin outer layer is actually worn away so the exterior of the shell is naturally pearly. However, this species is also made artificially pearly by manual removal of the outer layer, usually followed by polishing to a high gloss.  The species is argenteonitens, which means "bright silver".  The genus variously appears as Ginebis, Bathybembix, or Lischkeia. I'm not sure which one is technically more correct.  If you go here and type "argenteonitens" in the "species" box, you can see a number of specimens with varying degrees of "pearliness":

<a href="http://www.conchology.be/en/home/home.php" target="_blank"><!-- m --><a class="postlink" href="http://www.conchology.be/en/home/home.php">http://www.conchology.be/en/home/home.php</a><!-- m --></a>

If your shell is more than 50 mm it is most likely a "pearled" Trochus niloticus.  <span class="petit">--Last edited by Paul Monfils on 2009-04-21 19:21:39 --</span>