Louisiana Opal

Louisiana Opal

In “Louisiana Opal” at
http://lists.drizzle.com/pipermail/rockhounds/2012-February/037104.html
Gary Brown wrote,

“The note(s) on the Louisiana meteor crater got me
to thinking about Louisiana, and that got me to
thinking about Louisiana opal. Many of you (not YOU...
you already know about it) may not even know that
Louisiana has, or at least had, an opal deposit. I know
a bit about it, and I've got one piece squirrelled away
in my collection (picked up in London from Gregory,
Bottley, & Lloyd MANY years ago {And for a digression
note...talk about THEM!)) Anyway... cool stuff.
Anyone on the list have any details on it?”

It is sandstone cemented with precious opal. The
precious opal-cemented sandstone is part of the
Carnahan Bayou Member of the Fleming Formation

Some references to this precious opal are:

Denson, Daniel Ben, 1992, The identification and
delineation of a high velocity layer by seismic
refraction methods at the Hidden Fire Mine, Vernon
Parish, Louisiana. Master's University of New Orleans.
New Orleans, LA, United States, 51 pp.

Falster, A. U., Simmons, W. B., Griffith, K., Meurer,
K. J., and Montague, K. A., 1993, Precious opal from
Sabine Parish, Louisiana. Rocks and Minerals. vol.
68, no. 2, pp. 123.

Hessler, Susan, 1999, Precious Opal from Louisiana.
Rock and Gem. vol. 29, no. 10, pp. 28-33.

Hudson, Steve, 1987, Opal in Dixie. Rock & Gem. vol. 17,
no. 9, pp. 20-22, 64-67, 73.

Stevens, Ben F., 1999, Louisiana Opal: The One That
Dares to be Different. Exquisite Stone (P.O. Box 957)
Natalbany, Louisiana. 89 pp. (book)

Thomas, Leonard H., 1986, Elusive in Louisiana. Lapidary
Journal. vol. 40, no. 3, pp 54-56.

Voynick, Steve (2001) Louisiana Quartzite Opal. Rock
and Gem. vol. 31, no. 10, pp. 20-27.

The Monday, August 16, 1993, issue of the Times
Picayune has a revealing article the personalities
involved in the “Hidden Fire Mine.”

Note: Falstaff et al. (1993) has the wrong Parish
because they were told the wrong parish from where
the opal came.

The geology, including 1:24,000 scale geologic maps,
of the Fort Polk region is discussed in:

McCulloh, R. P, and P. V. Heinrich, 2002, Geology of the
Fort Polk Region, Sabine, Natchitoches, and Vernon
Parishes, Louisiana. Louisiana Geological Survey, Report
of Investigations no. 02-01, 82p

It was also asked,

“Can it still be found?”

The opal-bearing quartzite outcrops in T. 3 N., R. 11 W.
in the northwest corner of Vernon Parish. This site
is known as the “Hidden Fire Mine.” However, the
location where the precious opal was mined in now
closed to collecting because of legal liability issues
associated with abandoned mine workings and bad
feelings and legal problems that resulted in the closing
of the mine. Boise Cascade strictly enforces a ban on
anyone visiting the mine. Boise Cascade is very
insistent on prosecuting any trespassers who are
caught on this piece of their property, which they
constantly watch. They have not allowed anyone, even
Louisiana scientists, who are interested in studying
the site, permission to visit it.

Common opal has been reported elsewhere in Louisiana.
For example, Fisk (1940, p. 158) reports the presence of
"opaline noduies" in the Dough Hills Member of the
Fleming Formation in Rapides Parish. Large, up to football
size, nodules of common opal in the Carnahan Bayou
Member within southern Sabine Parish. It is possible
that precious opal might be found in the strata containing
this common opal. The distribution of the common opal
is discussed in:

Ambuehl, Alan Wayne , 1979, Surficial authigenic silica
of Gulf Coast tertiary formations. unpublished M.S. thesis,
Department of Geology, Louisiana State University,
Baton Rouge, LA 70803, 179 pp.

Best regards,

Paul H.