Avant, Arkansas Wavellite & Variscite - The deLinde Lease

Recent exploration at the world-renowned Dug Hill mineral locality near Avant, Arkansas is again producing outstanding specimens of wavellite and variscite.
Henry deLinde

First, a brief history about the deLinde mineral lease.  On June 28, 1965, Henry deLinde of Hot Springs, Arkansas applied to the Bureau of Land Management (BLM) for a wavellite and variscite prospecting permit in the Dug Hill area of Avant, Garland County, Arkansas. The property is located within the Ouachita National Forest. A prospecting permit was issued on November 1, 1965. On December 26, 1966 a small bulldozer was engaged to doze in the road and dig three shallow exploratory trenches in an east-west direction at the top of the ridge in the leased area. Wavellite and variscite were discovered in each of the three trenches. On February 16, 1967, two BLM representatives from McAlester, Oklahoma inspected the site and determined that requirements for an application of a Preference Rights Mineral Lease were in order. Henry applied for a Preference Rights Mineral Lease on August 16, 1967 and a ten year renewable lease, ARES 000008, (160 acres) was approved on March 1, 1968. The lease was subsequently reduced to eighty acres and is one of the oldest BLM leases in the state of Arkansas.

On December 1, 1975 a mining plan of operation was submitted to the BLM at McAlester, Oklahoma, approved by both the BLM and the U.S. Forest Service. In early January of 1976 a primitive access road was dozed in to the mine site. A rubber tired backhoe was used to excavate the trench areas. Approximately five dump truck loads of matrix were removed during a week of exploration. Excellent wavellite and variscite specimens were recovered. [See 1989 July/August issue of Rocks and Minerals].

In June of 1985 Henry submitted a detailed proposal to the U.S. Forest Service and three prominent mineral repositories that the lease area be set aside as a unique non-renewable resource. The proposal was rejected.

The lease has remained inactive since 1976 until June 21, 2008.

I first visited Dug Hill and the deLinde lease with Henry on December 6, 2006.  Here is a link to a web page showing our trip (A Walk in the Park).

I signed the contract to purchase the lease with Henry on March 30, 2007.  We submitted the paperwork to transfer the lease to the BLM Eastern States office on April 13, 2007.  BLM had to get the Jackson field office, the Forest Service and Minerals Management Service approval for the transfer.  The field office and the Forest Service approved the transfer by July 2007.  It took until December 4, 2007 to get MMS approval.  BLM approved the transfer on December 5 and approved our POA December 6.  We were finally good to go dig wavellite and variscite on the old deLinde claim.

Bad weather, locating and dozing in the old “grand fathered in” road, moving equipment, and other delays took another six months before Henry, Ray McGrew and I made our first dig on June 21, 2008.  Here are some photos of our first days dig (Dig Day 1).

Here are some photos of the wavellite and variscite we have been digging.  Click on the photos for a larger view.

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Most of our exploration has been in and near the eastern most pit #3 area.  We're still trying to get an understanding of the chert formation that contains the wavellite by trenching north-south across the east-west veins.  We spent one day at pit #2 but the chert was much harder than at pit #3 and we found very few open cavities with wavellite.  The seams were tight but the cat's eyes were larger then what we found at pit #3.
Pit #2 wavellite

For you serious rockhounds and geologists I've included the following excerpts from an article written by our friend, Art Smith.

ARKANSAS ALUMINUM PHOSPHATES: WAVELLITE, WITH VARISCITE AND  PLANERITE
by Arthur E. Smith

    "Wavellite has been collected in Arkansas since the middle of the 1800s.  A drawing of a typical wavellite specimen is included in Harvey (1886), Arkansas’ first state mineralogy.  Although way behind quartz with only spasmodic commercial production, wavellite is undoubtedly the second most commercially collectable mineral as specimens in Arkansas.  Dug Hill in Garland County was the source of most early wavellite specimens despite often being labeled as from Magnet Cove in Hot Spring County or from Montgomery County.   Dug Hill was in fact part of Hot Spring County until December 1842.   Even though not near it, Magnet Cove was erroneously reported as the source of early Dug Hill wavellite.  Shockley (1948) noted that Magnet Cove was not the source of Arkansas wavellite.  From 1842 Dug Hill was part of Montgomery County.  Garland County was formed in April 1873.  However, more complete data researched by Henry deLinde shows that the Dug Hill area in Buckfield Township was not annexed from Montgomery County until 1917.  It then becomes more obvious why the Montgomery County with Buckville, Avant, or Dug Hill on wavellite labels has persisted for so so long.

    The color of Arkansas wavellite may be colorless, green, yellow, white, black or pale blue.  The color is caused by the valence of vanadium provided there are no other chromatic elements present (Fosterer and Schaller 1966 and Holt 1972).  V3+ imparts a green color, V4+ imparts blue, and V5+ imparts yellow.  The absence of vanadium results in white or colorless wavellite.  However, the wavellite from the Christy vanadium deposit, Magnet Cove is white in contrast to the wavellite at the Union Carbide vanadium mine at Wilson Springs that is either white or a medium to pale green.  The black wavellite is probably caused by numerous minute included shale particles.  EDS/SEM analysis of back and green wavellite at Mauldin Mountain is identical.  Variscite usually occurs in some shade of green but in some localities it is inconspicuous and in others absent or at least, not recognized or reported.  Metavariscite has been reported from X-ray data at Mauldin Mountain but individual crystals have not been observed (Smith 1985).  Variscite is orthorhombic and metavariscite is monoclinic so there should be some visual distinction of the crystals except when the crystals are too small to see or possibly present as pseudomorphs.

    Aluminum and iron phosphate minerals are relatively common in Arkansas if one knows where to look for them.  The aluminum phosphates, wavellite and variscite are commonly associated with the Big Fork Chert Formation.  Any outcrop or exposure of  the Big Fork Chert has the potential of containing at least some wavellite and variscite.  However, the Big Fork Chert seldom looks like typical chert.  Instead it looks more like gray or brown sandstone or a light to dark gray shale.  Often where the formation is exposed its bedding is steeply dipping or near vertical.  This generally makes hand digging extremely difficult.  Planerite may also occur in the Big Fork Chert.  Turquoise is reported from the Arkansas Novaculite and mined on Porter Ridge in Polk County but Howard (2007) reports that many of these occurrences are actually planerite.  These two blue to greenish blue minerals can generally not be visually distinguished from each other.  Though turquoise has copper and planerite does not.  It can be assumed that most of what has been called turquoise in Arkansas may actually be planerite.  Minute submicroscopic crystals of both minerals have been observed but they generally occur as vein fillings.  The turquoise is an iron rich variety called rashleighite.  Hemispheres of planerite from one to several millimeters across are present at Mauldin Mountain.

    Where variscite and wavellite occur together, the variscite has usually been deposited first.  Planerite occurs under or on wavellite and most variscite.  Cacoxenite seen only with wavellite at the old county pit at Mauldin Mountain is the last phosphate to form occurring on wavellite.

    The iron phosphates minerals generally occur in the Arkansas Novaculite.  The iron phosphate minerals include dufrenite, kidwellite, rockbridgeite, cacoxenite, strengite, lipscombite, phosphosiderite, beraunite, and probably others.  However, there are places where the iron and aluminum phosphates will occur in the same quarry or even together.  For a review of these phosphates and other Arkansas phosphate minerals, the article by Barwood and de Linde (1989) is recommended.  Perhamite and artsmithite, two other phosphates were discovered and identified after that article was written (Smith 2005) along with many of those at the Union Carbide Vanadium mine (Howard and Owens 1995).

    Opinions on the formation of wavellite and variscite vary.  Early investigators favor a hot springs or hydrothermal formation though with the occurrences mostly limited to the Big Fork Chert Formation, some stratigraphic control is suggested.  However, in recent years the discovery of occurrences at Crows, the Union Carbide vanadium mine at Wilson Springs, Magnet Cove, and the Funderburk mercury mine may indicate a more widespread distribution in other formations and possibly multiple origins in the Ouachita Mountains. Most of these formations may have enough phosphorite already in them to form phosphate minerals and so it is perhaps the copper, iron, aluminum and other elements that are brought in and are more critical to what phosphate mineral forms in what formation and not the amount or availability of phosphate.  Al Kidwell always felt it was local hot spring actions that altered the wavellite into crandallite but earlier hydrothermal activity may have originally precipitated or formed the variscite, wavellite and planerite.  Iron oxide is generally a very late mineral in the wavellite deposits and may be the reason for the general lack of iron phosphate minerals associated with them except for minor cacoxenite at the old county pit at Mauldin Mountain in a small goethitic area, the Union Carbide vanadium mine at Wilson Springs, and at the Fodderstack Mountain wavellite occurrence.

    Dug Hill, near Avant (AKA Buckville and Cedar Glades) is located on a 3.5 mile long ridge about 1.5 miles north of Buckville, a vacation community, on the north shore of Lake Ouachita, in Sec. 10 & 11, T1S, R22W.  The Dug Hill location did not get its name from the numerous small diggings on the side of the hill but according to Hugh Miser of the U.S. Geological Survey, it was named because they dug a deep cut on the top of the hill for the road leading south to Avant (Smith 1987).  Dug Hill can be reached by going south to Buckville 1.9 miles from the turnoff from State Highway 298.  A small borrow pit on the left (east) at the top of the incline is at the top of Dug Hill.  Numerous shallow diggings along the north side of the hill for quite a distance to the east.  A dim trail leads east at the base of the hill.  It requires a steep climb up to the wavellite pits.

    Most advanced Arkansas collectors will agree that Dug Hill was the early source of most of Arkansas wavellite labeled from Pencil Bluff or just Montgomery County and even from Magnet Cove, Hot Spring County.  This will include most green wavellite and variscite produced prior to 1978 when Mauldin Mountain in Montgomery County started to yield a lot of wavellite in good specimens.  The last attempt at mechanized commercial mining at Dug Hill was illegal and done before 1975.  The large pit on the side of the hill bears testimony to the operations.  Broughton (1975) has a picture and description of this illegal pit but did not realize it was on Dug Hill. His directions to the location will not work today.  Hand digging was and evidently still is permitted by the Corps of Engineers who control this area because it is in the Lake Ouachita watershed. As a result of no commercial mining, little new Dug Hill wavellite has been available since 1980 when the site was reclaimed and planted with pine trees.

    Dug Hill wavellite is generally a medium green with small amounts of dark green or even a light or yellow green.  It is generally in broken spheres with a defined radiating internal structure though some specimens also display a strong concentric structure.  The spheres average less than 3 cm in diameter but may reach 5 cm in diameter.  Each ray of the internal structure represents an individual elongated crystal that may change color along its length and be terminated on the sphere’s outer surface.  Unless good-sized cavities are available, the wavellite forms in seams and so there just may be a thin, green, radiating circular pattern on the matrix that just shows partial development  of the complete  sphere or hemisphere.  These were more typical of early Dug Hill specimens particularly before 1960.  Also some free standing individual microscopic crystals and groups of these crystals have been collected.  They are usually transparent and a very pale green and make attractive micromounts.

    Variscite, as bright green drusy coatings, is common in some areas.  When variscite viewed under a microscope, rectangular crystal faces or freestanding intergrown groups of crystal may be observed.  Making the variscite more than the very thin green coating that it may appear to be without magnification.   At Dug Hill the variscite seldom occurs in the same specimens as the wavellite.  One exception was a small area in the corner of the illegal pit.  The author saw the area and dug out a few small dark green wavellite hemispheres on variscite.  Later I found that Clyde Garman had originally discovered it and dug most of it out.  It consisted of an irregular, vuggy, milky quartz vein that had medium green wavellite as spheres and hemispheres up to about 1 cm on green variscite.  Clyde had recovered all of it in the late 1970s and it was obtained by a swap from him that was in a box that he kept under his bed at his home in Pencil Bluff.
Small amounts of white crandallite pseudomorphs after wavellite have been observed at Dug Hill but they are not common.  Gray spheres from 1 to 2 cm in diameter are common in some areas.  They may have some green wavellite embedded in them and may be alteration pseudomorphs of an amorphous phosphate after wavellite or they could be just impure and incompletely formed spheres of wavellite.  They seldom have any internal structure like the wavellite.  A recently obtained small specimen that is mostly wavellite has this gray material most prominent on the outer edges of the wavellite spheres.  It only rarely extends to the center and would seem to be a replacement pseudomorph. The composition of the X-rayed amorphous material has not been analyzed to tell which phosphate mineral it may be.

    The matrix rock for most of Dug Hill wavellite is a gray to brown sandy phase of the Big Fork Chert.  It is contorted and has mostly vertical or steeply dipping beds.  In some areas it is brecciated and faulted.  Angular cavities to several cm across may be present in breccia zones.  Cavities are usually filled with the typical Arkansas red, sticky, clay but may contain the hemispheres or spheres or wavellite.

    The DeLinde (now Stuart Schmitt) lease on the east end of Dug Hill is several hundred yards east of the Dug Hill diggings and is on the same ridge.  This deposit had been under lease to Henry deLinde of Hot Springs for over 40 years by the Bureau of Land Management.  In the early 1970s the deposit was worked from three small pits, then back-filled.  New mining is now being done (summer of 2008)  by Stuart Schmitt who bought the lease from Mr. deLinde in December 2007.  The wavellite is similar to that at Dug Hill, though some of it has a bluish to bluish gray tinge on the outer surface.  Excellent specimens of wavellite and bright green variscite were recovered along with some white crandallite pseudomorphs after wavellite.  Henry Barwood collected some cacoxenite from this location in 1979."

Stuart Schmitt
60 Mary's Eagle Trail
Mount Ida, AR 71957
870-867-2443
stu@arcrystalmine.com
www.arcrystalmine.com