[meteorite-list] Tsavorites
From: Pekka Savolainen <pekka.savolainen_at_meteoritecentral.com>
Date: Thu Apr 22 10:30:00 2004 Message-ID: <3F75FEC5.2010401_at_dlc.fi> --------------050006000200010301090206 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Hello, all, The hardness of obsidian or volcanic glass is 5 - 5―, moldavites 5―. Dispersion of obsidian is 0,010 and moldavite doesnīt have it at all. The difference is not enough to make a valid classificaton with this way. The refractive index is 1.48 - 1.50 for both, so the refractometer is useless in this problem. Also both are amorphics. In fact also Moldavite + other tektites are glass, Si02 + AL2O3, so itīs very, very difficult to find the difference from dumbled or cutted pieces. Usually raw Moldavite has clear characters, typical for it, and so do also the other tektites. Any african ones I have seen, donīt have this typical appearance. Absorbtion for green obsidian is 680, 670, 660, 650, 635, 595, 555, 500 . With Moldavite, usually the absorbtion canīt be ordered. If someone on the list happens to have this material and a spectrometre nearby, it would be nice to hear the results about the absortion-spectre of the material. I gave specimens I had, to my friend, who is a gemmologist, FGA. Will call her, and ask her to check the spectrum, if she still have the pieces left. It may take some days, but will let you know the results. Well, in fact I can bet, the spectrum will show chrome, if the material is from Kenya and near Tsavo...;- best regards, pekka s Impactika_at_aol.com wrote: > > > One easy way to differentiate them could be the hardness. > Tsavorite, and most garnets, are 7 to 7.5 on the Mohs hardness scale. > Glass, natural or man-made is a lot softer, 5 (I think). > Now, what is the average hardness of tektites? > > Anne M. Black > www. IMPACTIKA.com > IMPACTIKA_at_aol.com > IMCA #2356 -- Pekka Savolainen Jokiharjuntie 4 FIN-71330 Rasala FINLAND + 358 400 818 912 Group Home Page: http://www.smartgroups.com/groups/eurocoin Group Email Address: eurocoin_at_smartgroups.com --------------050006000200010301090206 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit <html> <head> </head> <body> <br> <br> Hello, all,<br> <br> The hardness of obsidian or volcanic glass is 5 - 5½,<br> moldavites 5½. Dispersion of obsidian is 0,010 and<br> moldavite doesn´t have it at all. The difference is not<br> enough to make a valid classificaton with this way.<br> <br> The refractive index is 1.48 - 1.50 for both, so the<br> refractometer is useless in this problem. Also both<br> are amorphics.<br> <br> <br> In fact also Moldavite + other tektites are glass, <br> Si02 + AL2O3, so it´s very, very difficult to find the<br> difference from dumbled or cutted pieces. Usually <br> raw Moldavite has clear characters, typical for it, and <br> so do also the other tektites. <br> <br> Any african ones I have seen, don´t have this typical <br> appearance.<br> <br> Absorbtion for green obsidian is 680, 670, 660, 650,<br> 635, 595, 555, 500 . With Moldavite, usually the <br> absorbtion can´t be ordered.<br> <br> If someone on the list happens to have this material and<br> a spectrometre nearby, it would be nice to hear the results<br> about the absortion-spectre of the material.<br> <br> I gave specimens I had, to my friend, who is a gemmologist,<br> FGA. Will call her, and ask her to check the spectrum, if she<br> still have the pieces left. It may take some days, but will let<br> you know the results.<br> <br> Well, in fact I can bet, the spectrum will show chrome,<br> if the material is from Kenya and near Tsavo...;- <br> <br> <br> best regards,<br> <br> pekka s<br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <a class="moz-txt-link-abbreviated" href="mailto:Impactika_at_aol.com">Impactika@aol.com</a> wrote:<br> <blockquote type="cite" cite="mid:153.248bf73a.2ca74756_at_aol.com"><font face="arial,helvetica"><font color="#000000" size="3" family="SANSSERIF" face="Arial" lang="0"><br> </font><font color="#000000" size="2" family="SANSSERIF" face="Arial" lang="0"><br> One easy way to differentiate them could be the hardness. <br> Tsavorite, and most garnets, are 7 to 7.5 on the Mohs hardness scale. Glass, natural or man-made is a lot softer, 5 (I think). <br> Now, what is the average hardness of tektites? <br> <br> Anne M. Black <br> www. IMPACTIKA.com <br> <a class="moz-txt-link-abbreviated" href="mailto:IMPACTIKA_at_aol.com">IMPACTIKA@aol.com</a> <br> IMCA #2356</font></font></blockquote> <br> <pre class="moz-signature" cols="$mailwrapcol">-- Pekka Savolainen Jokiharjuntie 4 FIN-71330 Rasala FINLAND + 358 400 818 912 Group Home Page: <a class="moz-txt-link-freetext" href="http://www.smartgroups.com/groups/eurocoin">http://www.smartgroups.com/groups/eurocoin</a> Group Email Address: <a class="moz-txt-link-abbreviated" href="mailto:eurocoin_at_smartgroups.com">eurocoin@smartgroups.com</a> </pre> <br> </body> </html> --------------050006000200010301090206--Received on Sat 27 Sep 2003 05:19:01 PM PDT |
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