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Stonetree Opal Mine (WRT Stonetree claim; BLM-NMC No. 865655), WRT Stonetree group ("Dominion Opal Mine"), Virgin Valley, Humboldt Co., Nevada, USAi
Regional Level Types
Stonetree Opal Mine (WRT Stonetree claim; BLM-NMC No. 865655)Mine
WRT Stonetree group ("Dominion Opal Mine")- not defined -
Virgin ValleyValley
Humboldt Co.County

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Latitude & Longitude (WGS84):
41° 51' 40'' North , 119° 2' 36'' West
Latitude & Longitude (decimal):
Locality type:

The Stonetree deposit was one of the earliest mining claim locations in the Virgin Valley Mining District. Although known to exist much earlier in time, it was first "officially" reported by D.B. Sterrett in 1913 as being owned by "several parties". At one time the mine was owned by renowned Flora H. Loughhead ("Lockheed") Gutierrez, and was referred to in 1916-1918 as the "Giant Tree" Opal Claim, and was sold by Gutierrez to the Rainbow Ridge Mining Company in 1918. Between 1918 to 1940, the surface float and alluvial (placer) deposits of opal were exhausted and the claim subsequently became idle and abandoned. It was relocated as a placer deposit in 1966. In 2004 it was located as a lode (in-place) deposit when it became a part of the ten-claim WRT Stonetree claim group by the Wentzell Revocable Trust. Annual Assessment work and development by agents of The Wentzell Revocable Trust from 2007 to present uncovered large amounts of precious black, crystal, jelly and other opal types, including a large harlequin black opal. The claim obtained its name from the large 30+ foot petrified tree on the property. Mining efforts are undertaken in such a way to protect this landmark fossil for future generations of the public to enjoy. The Petrified Tree is property of the United States and cannot be mined, damaged or claimed.

The Stonetree deposit is similar to all of the other precious-opal bearing deposits in Virgin Valley. The mining claims are underlain by in-place, horizontal ash, tuff, and tuffaceous sandstone beds. The opal-bearing horizon can be traced and followed and averages more than 4 feet (1.2 m) thick and consists primarily of light-colored bentonite containing varying amounts of petrified wood, rhyolite pebbles, ash, and opal. Precious opals are usually found in the upper half of the horizon. The opal-bearing layer is continuous and in-place. The precious opals which are mined from this deposit are as bright as, if not brighter than, opals from the other area mines. The largest precious opal found on this group of claims was approximately four (4) pounds. Petrified wood is not mined on any of the claims but the precious opal is found in association with petrified wood.

The WRT Stonetree lode mining claim is owned by Alvin W. Wentzell Jr. & TWGT. Dominion Opal Mines has been, and continues (2018) to be in charge of mining and assessment work operations through its agents. Officially known as the WRT Stonetree Lode Mining Claim, BLM-NMC#865655.

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Standard Detailed Strunz Dana Chemical Elements

Commodity List

This is a list of exploitable or exploited mineral commodities recorded at this locality.

Mineral List

1 valid mineral.

Detailed Mineral List:

Formula: SiO2 · nH2O
Reference: Sinkankas, John (1959) Gemstones of North America. Figure 30 at page 116.
Opal var: Precious Opal
Formula: SiO2 · nH2O
Reference: Sinkankas, John (1959) Gemstones of North America. Figure 30 at page 116.
Opal var: Wood Opal
Formula: SiO2 · nH2O
Reference: Christopher N. Wentzell
'Petrified Wood'
Reference: Christopher N. Wentzell

List of minerals arranged by Strunz 10th Edition classification

Group 4 - Oxides and Hydroxides
Opal4.DA.10SiO2 · nH2O
var: Precious Opal4.DA.10SiO2 · nH2O
var: Wood Opal4.DA.10SiO2 · nH2O
Unclassified Minerals, Rocks, etc.
'Petrified Wood'-

List of minerals arranged by Dana 8th Edition classification

Group 75 - TECTOSILICATES Si Tetrahedral Frameworks
Si Tetrahedral Frameworks - SiO2 with H2O and organics
Opal75.2.1.1SiO2 · nH2O
Unclassified Minerals, Mixtures, etc.
var: Precious Opal-SiO2 · nH2O
var: Wood Opal-SiO2 · nH2O
'Petrified Wood'-

List of minerals for each chemical element

H OpalSiO2 · nH2O
H Opal (var: Precious Opal)SiO2 · nH2O
H Opal (var: Wood Opal)SiO2 · nH2O
O OpalSiO2 · nH2O
O Opal (var: Precious Opal)SiO2 · nH2O
O Opal (var: Wood Opal)SiO2 · nH2O
Si OpalSiO2 · nH2O
Si Opal (var: Precious Opal)SiO2 · nH2O
Si Opal (var: Wood Opal)SiO2 · nH2O


Sort by

Year (asc) Year (desc) Author (A-Z) Author (Z-A)
Sterrett, D.B. (1914) Gems and Precious Stones chapter in United States Geological Survey Mineral Resources U.S., for 1913. Pages 677-680, at 677.
Sinkankas, John (1959) Gemstones of North America. (D. Van Nostrand Company, Princeton, N.J.). Figure 30 at page 116.
Butler, Gail (1987)(Sept.) Opal in Virgin Valley. Rock & Gem Magazine, p. 36-38.
Castor, Stephen B. (2005) The Nevada Mineral Industry 2004. Nevada Bureau of Mines and Geology Special Publication MI-2004, University of Nevada, Reno. At page 53 under "Gemstones."
United States Geological Survey (USGS) Minerals Yearbook, 2004, Volume 2, Area Reports, Domestic; at page 30.4 under "Gemstones."
Mining Claim Files for NMC865653 through NMC865662 (WRT Pleasures & Stonetree Group claims). U.S. Department of the Interior, Bureau of Land Management, Nevada State Office, Reno, Nevada USA.
Historical documents pertaining to the Virgin Valley Mining District in the possession of Christopher Wentzell & The Wentzell Revocable Trust.
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