Jay, the tabbies found in Arkansas and many other places including the Burgin property in NC definitely resemble gwindels, but they are not.  Gwindels actually have a twist in their structure as it comes up from the base.  Even though the picture John posted does not show that twist it is there and can be seen if you held it yourself.  I even have crystals with a twist similar to what you would see in a gwindel but I know they are not gwindels because it does not meet all the criteria.  Quartz naturally has destortions in its structure and these destortions can account for some odd shapes such as bent quartz, and even tabbies with a slight twist or bend.  Here is a valuable resource that I believe adequately describes the subtle nuances in the shape and morphology that qualifies a true Gwindel:

http://www.quartzpage.de/gwindel.html

Don't show them to Scott, Jay. He says nope to everything.
Show them to me, and you'll have a real Gwindel!

Another shot

One more

Those are nice crystals, Jim. I love unusual stuff like that
and think they are as neat as any Gwindel even if they
technically aren't. I like Jays' name for them "Tabby Chains" but
we ought to be able to come up with a few more names for
some of the different formations we find here.
Have you soaked those in any Iron Out or oxalic yet?

And just to head off any possible debates on the subject;
I agree with John in that, as far as I know, there has never
been a documented Gwindel found in North America.
Anyone who thinks they have found a Gwindel in NA
seriously ought to send it to the Smithsonian for proper
documentation. To have the first ever documented Gwindel
from NA would be well worth it in my opinion!
I ought to put together a whole box of the "questionable"
ones I have found and send it off to them.

Joe