[meteorite-list] Brown Crystals Orange Crystals...was advice needed

From: Mr EMan <mstreman53_at_meteoritecentral.com>
Date: Thu, 19 Feb 2009 23:08:15 -0800 (PST)
Message-ID: <764555.58990.qm_at_web55204.mail.re4.yahoo.com>

Hello Jim,

The brown opaque elongated lozenge-shaped crystal(s) which are in cross section in the thin section, very much resembles titanite CaTi[O|SiO4] formerly known as sphene. The cross-section shape is classic for sphene IMO. Sphene is something like 2.5 to 3 times longer on the width axis than on the height axis but this is just memory so please verify that yourself. Mindat.org is a place to do specific mineral searches, BTW.

There is also a complicated Titanium bearing mineral called titanate with an"a":
CaAl2Si2O8-Fe2TiO4-FeTi2O5 which I assume as some spinel form based on the description at mindat.org. My guess is that this forms upon interaction with Fe-vapor in subsequent metamorphoses by impact melting of the lunar soil??? I am not saying the crystal you have is titanate but just wanted to impress you with my Googling skills. Just kidding! I mentioned it in case you accidentally get sent to that page owing to similar spelling.

Rutile, TiO2 forms blades, needles, and hexagonal prisms--Yet another titanium mineral common in lunar rocks. I caught a slide suggesting a hexagonal "orange structure was possibly a glass sphere" but given the rays within it, that might be rutile.

All these minerals have been found in lunar rocks /meteorites AFAIK.

For what it is worth, have you considered a cosmic ray track count as well? I don't know the cost but you may have enough left over from TS prep to or the TS itself.

Congrats on the research and specimen prep so far: Impressive!
Elton

--- On Fri, 2/20/09, Suzanne and Jim <suzieandjim at yahoo.com> wrote:

> From: Suzanne and Jim <suzieandjim at yahoo.com>
> Subject: [meteorite-list] need some advice,

 
 
> I am trying to determine the nature of the
> orthorhombic-like opaque red/brown crystals I have seen in a
> slice I am considering having analyzed.
Received on Fri 20 Feb 2009 02:08:15 AM PST