Colors of the McGuinness Mine

mcguinness_property.jpg (32783 bytes)
mcguinness_pit_east3.jpg (41132 bytes) The McGuinness turquoise mine is located at an elevation of about 7700 ft at in the eastern foothills of the Toiyabe Range in central Nevada. It has also been known as the Gem, or McGuinness Gem. The location is roughly about 200 miles east of Reno and about 10 Miles NE of Austin. Cold weather and snow at this high elevation make the property inaccessible for about 4 to 5 months of the year.  Turquoise was first found in this area in 1930. After the initial discovery, the property was purchased worked periodically on a small scale by Mr. George McGuinness of Oakland, CA during the 1930s and 1940s.  The mine takes its name from him, and most of the workings at that time were underground with a few small surface pits.
Later, the mine was worked on a much larger scale by mechanized equipment in the 1960s and 1970s and  produced large amounts of  very high grade turquoise. This was during the time when turquoise most popular and prices were very high. The bulldozer workings were done at the locations of Mr. McGuinness's underground adits, so that the pits excavated out the old workings. Historically, the mine produced about $40,000 worth of turquoise prior to 1960,  and an estimated at $250,000 since 1960. The mine is large enough that is named and shown on the 7.5 minute USGS topo map for the area. It is also specifically mentioned in a number of books about turquoise. The top grade turquoise at the McGuinness mine  is a deep bold blue with contrasting angular black matrix. The turquoise is deposited in cracks in the rock and several parallel breccia vein zones averaging about two feet wide. Thin coatings of turquoise are common in many locations on the claims. In many places these veinlets are thick enough to be cut as gemstones. mcginess_air_photo2b.jpg (50922 bytes)
mcguinness_pit_west3.jpg (35444 bytes) The breccia "veins" in which the turquoise occurs are fault zones of broken rock that cut through chert and shales.  Turquoise does not fill the entire breccia zone, but turquoise occurs between the broken rock cementing it together, sometimes as small veinlets of turquoise within it, and occasionally as turquoise nuggets. Veinlets are far more common than nuggets at this property, with nuggets only making up maybe 1 or 2 percent of the total production. Veinlets of  turquoise are  present in all of the workings, in fact turquoise is widespread throughout the mine area. Turquoise can also be found  in the pit walls, the mine dumps and in various rock outcrops in around the claim area.
There are two good sized open pit excavations on the property, and a number of smaller ones. The two large workings are known as the east and west pits as they lie about 750 feet apart at the east and west ends of the McGuinness Gem 1 claim. The two larger  pits are just over 300 feet in length. There are a number of smaller pits as well and these are about 50 to 150 feet in size. All the workings currently visible at the mine were made by a bulldozer. Strong outcrops with much visible turquoise lie between the east and west pits at the mine which shows that turquoise present in the area between the two pits. mcginess_topo3.jpg (52937 bytes)
mcguinness_rough1b.jpg (30638 bytes) This photo shows a mix of fine rough McGuinness Turquoise. The coin in the foreground for scale is a quarter. All of the rough shown is blue, even the greenish larger piece on the left is just coated with a thin layer of rust-yellow colored clay. Much of the turquoise from this mine is coated with a thin layer of rust colored clay. Although the McGuinness produces some green material, blue colors, medium to deep in color by far predominate over any other shades. Some of the green rough probably contains little copper and is likely to be variscite. Although some old books on turquoise sources indicate that much of the turquoise initially mined from the McGuinness was only of "fair" grade, this has not been true of the later workings done in the 1960s and 1970s.  The coin in the foreground is a quarter, shown for scale.
Turquoise of all grades and qualities, from fair to excellent is present at the mine, but a higher than normal percentage of the McGuinness turquoise is hard and of gem quality, well suited to use without any treatments or stabilizations. The best McGuinness is very deep blue and slightly translucent. The photo at right shows a small veinlet of greenish variscite (or possibly turquoise) in place in a breccia zone in the walls of the west pit. These breccia zones of broken rock are actually old fault zones. The turquoise forms in cracks in the rock where solutions bearing the necessary chemicals form turquoise seep down through the rock. In places, the entire breccia is turned to turquoise, so that the turquoise surrounds the broken breccia rock. At the present time, we are only reworking the old mine dumps, but so far these have produced sufficient turquoise to meet our needs. turq_veinlet2.jpg (29185 bytes)
mcginess_turquoise.jpg (19034 bytes) This photo shows some nice deep blue gem quality material with the typical contrasting angular black matrix that this mine produces. The upper stone shows an unusual smoky purple coloration. The mine produces good, hard turquoise, including some clear material with no matrix, but virtually no material with a spiderweb type of matrix pattern.
This photo shows a beautiful bracelet of deep blue, high quality turquoise from the McGuinness Mine.
A pair of blue/green matching earrings from the McGuinness Mine. Be sure to check out the Jewelry we have from the McGuinness and other mines by Turquoise Jewelry.
This is the beautiful view looking east from the McGuinness Mine. This view is toward the Damele and Godber (Burnham) turquoise mines which lie on the far side of the mountain range 10 miles in the distance. We acquired the McGuinness mine in the spring of 2005. We continue to work it on a small scale as the weather and our schedules allow. The valley below has several still active cattle ranches. mcguinness_view2.jpg (15869 bytes)
If you are interested in purchasing some of the turquoise from the McGuinness mine, check the links shown below for the rough and finished gems we have available for sale. Here is a link for the  Turquoise Cabochons

Nevada Outback Gems

Find out more by checking out All of Our links below:
View our Premium Contemporary Turquoise Jewelry - Wearable Artwork! View our Unique Gem Quality Turquoise Cabochons
Premium Jewelry, with Gemstones of all types Top Quality Loose Gemstones - Gemstones of all types
Rare Crystals and Gemstone Rough, all types including Turquoise Check out our EBAY Auctions of Jewelry, Gemstones and Rough
How to make a purchase, information and terms More information about us - Nevada Outback Gems
About Nevada Turquoise Contact us - we want to help
More Info about Turquoise, the Beautiful Gem Nevada Outback Gems Homepage
Take a virtual tour of our turquoise mines Our Free Colored Gemstone Information Encyclopedia
Chris' Adventures Prospecting for Gold, Silver, Turquoise and other Gems Nevada Outback Library and Bookstore - Learn more!
Nevada Outback Gems Website News More Info about Gem Cutting