Wow that is very cool!  It reminds me of some of the "white cap" crystals that came from Kersey Valley in Guilford County, NC, that have a glass clear central core, with a rind of milky quartz.  Of course the clear quartz is pure, and a period of interrupted growth allowed inclusions of fluids and gasses to incorporate within the quartz cap and give it that milky look. It's interesting that the amount of gas and fluid inclusions not only determines how milky the quartz is, it also influences the form of the crystals.  Nice photos.

Here are several more pictures of specimens mainly found at the Silver Lake location in Raleigh, NC.  I took these photographs with the intention of emphasizing the unusual beveled faces found on many tessin habit quartz crystals.  I believe the bevels consist of a combination of "s" and other intermediate type faces.

Look here for reference into "s" faces:  http://www.quartzpage.de/crs_intro.html

I'm really enjoying these pictures, Scott!
Of course it is very hard to claim the derivation for each and every one of these anomalous faces
but I think you will have to agree, having seen many in situ
growing amongst the mica, that contact with mica has got to be the cause of many of them.
How many different crystals did you use for the pics above?


I have to add some pics of the one crystal from the same area I found recently
with very similar signs. I need to get better magnification before I can check for any monazite.
Here are different angles of the whole crystal.

This is a recent surface find from that area with a nice patch
of the red rutile, another possible culprit for the unusual formations.

JoeM wrote on Jul 14^th, 2014 at 10:43pm:


A mica interaction would not be responsible for the beveled faces I photographed in this thread.  I certainly understand your point and how it closely it might resemble the striations one sees with a mica contact.  These particular faces are consistent in angle and position to assume "s" face expression.  Also, most if not all the crystals that display these beveled edges do not occur on just one random edge, but multiple edges on the same crystal.  This would imply something more than a random coincidental contact with mica.

I drew up a quick diagram below to show how the "s" faces specifically are involved and how they can be recognized in the photos.  As you can see in the left image, the "s" face always occurs parallel or juxtaposed to the lower left or right of one of the rhombohedral or termination faces.  In the right image I simply duplicated and carried this "s" face downward along the edge of the prism.  You can see how the angle remains exactly the same as the original "s" face as it is repeated going down the prism.  You can see this exact "s" face angle repeated in my specimen photographs.

Take a look again at images z39 -- z43 above as you will be able to identify the "s" face with its relationship to the rhombohedral or termination face.  You can see the same angel is preserved as it travels down the prism.