November 4th: The Role of Spruce Pine Quartz in Astronomy


Date: November 4, 2011

Title: The Role of Spruce Pine Quartz in Astronomy

Podcaster: David Biddix

Link: David’s website:

Description: Spruce Pine, North Carolina, a small town in the western part of the state, has a storied history related to astronomy instruments. The Spruce Pine Mining District, a geographical area that features significant deposits of mica, feldspar, and quartz, has played a significant role in astronomy for the past 80 years. The mirror in the 200 inch Hale Telescope at Palomar Mountain is made from quartz mined in the District in the 1930s. Today, all electronic devices including computers, televisions, cell phones, mp3 players, and other gadgets owe their existence to ultrapure quartz mined near Spruce Pine. In this podcast, you’ll learn how this down-to-earth small town helps astronomers reach for the stars.

Bios: David Biddix is a local historian who has published two books in Arcadia Publishing’s Images of America series with co-author Chris Hollifield: one on Spruce Pine, North Carolina and one on Little Switzerland, North Carolina. He was born and currently lives in Spruce Pine. David’s interests include amateur radio, astronomy, and history.

Alex Glover (guest on the podcast) is the Director of Mining and Environment for Active Minerals International, LLC. He is a licensed professional geologist in nine southeastern states in the United States and has lived in the Spruce Pine area since 1997. He is interested both in the geology of the Spruce Pine Mining District and in its history, which goes back some 170 years.

Sponsor: This episode of “365 Days of Astronomy” has been sponsored by — NO ONE. We still need sponsors for many days in 2011, so please consider sponsoring a day or two. Just click on the “Donate” button on the lower left side of this webpage, or contact us at


For the 365 Days of Astronomy, I’m David Biddix, a native and resident of Spruce Pine, North Carolina in the United States of America. Spruce Pine is a small town in the western part of North Carolina that has unique ties to astronomy. It was here some 79 years ago that Corning Glass Works purchased mined quartz which was used to create the mirror of the famous 200 inch Hale Telescope at Palomar Mountain in California. Today, Spruce Pine continues to play a major role in astronomy, especially through electronics.

I became interested in astronomy as a child, reading popular books in the 1970s on telescopes. I became enthralled with the Hale Telescope, which was at the time, the largest optical telescope on earth. It was an honor it would hold until 1976, when the BTA-6 telescope opened in Russia. The Hale was a marvel of technology in the 1930s and 40s, and continues to produce cutting-edge science even today. It has wowed generations with both its size and the beautiful images it has generated over the past 63 years. I’ve always wondered why ore from the Chestnut Flats Mine near Spruce Pine was chosen for the telescope’s mirror. Recently, I had a discussion with Alex Glover, a local geologist and mining historian who is very familiar with what is known as the Spruce Pine Mining District, a 10 mile-long, 5 mile-wide outcropping of rock from early in earth’s history that contains some of the purest minerals in the world and is the economic lifeblood of this region. This purity was the reason Corning Glass came to this region to find materials for the mirror. Alex speaks about what types of minerals are found in the district.

(37 seconds) There’s another name for these deposits: Alaskites. Alaskites are felspathic-rich granites, and we generally in the Spruce Pine mining district have about 65% feldspar, which is a potassium-sodium/potassium-aluminum silicate and then quartz which of course is silica and oxygen and then we have also mica. Muscovite mica is here and we get garnets and other accessory minerals but the majority of the pegmatites are feldspar and the number two mineral is quartz.

Our discussion then turned to the Hale Telescope. Imagine my surprise when Alex told me that the great telescope’s mirror was made of ore that was usually discarded from the mines here.

(33 seconds) When the deposits were first being mined, the quartz was thrown away. It was thought to have no value. The high value material was the mica and then came the feldspar for ceramic use and glass use and back when the Chestnut Flats mine was being mined, the miners would chip off a piece of quartz and throw that away, chip off a piece of high-purity feldspar and throw it in a wagon or a wheelbarrow, and they’d chip off a nice book of mica and throw it in another wheelbarrow.

Corning was going to make the mirror using their then-new Pyrex technology, and such a large piece of glass required quartz that was exceptionally pure. Alex explains how Corning came to choose the Chestnut Flats Mine:

(1 minute, 22 seconds) They would have been looking for as pure a quartz as they could find. Impurities generally in quartz would be titanium…you can get a rutilated quartz, which is one of the minerals which titanium is derived from is rutile, and so you can get rutiliated quartz, you can get high-iron quartz, you can get amethyst, which is a quartz with contamination of iron which is what turns it purple. You can also get rose quartz. You don’t want those contaminations, especially iron-bearing minerals, so they would have been looking for a quartz that was basically free of iron, and these deposits were known to have been free. There are many quartz deposits and feldspar deposits around the world. In fact, quartz is the most abundant mineral on Earth’s surface. The number two mineral is feldspar. So these things are in igneous, metamorphic, and sedimentary rocks, but the general lack of iron is rare. So that’s what they were looking for, and somehow they found out the Spruce Pine Mining District and the purity of the quartz, even though at that time the quartz was being thrown away.

(48 seconds) And I imagine that somebody noticed that there was a large quartz vein there. It was a smoky quartz. Smoky quartz is usually smoky because it’s been irradiated by a radioactive source during magma cooling, so that was the case here. Somebody must have tested that for purity, and it was high purity, even though today, some of the purities of the Chestnut Flats Mine don’t meet stringent quality parameters to make the super high-quality quartz, but at that time, that was probably the highest purity known maybe in the world. And they knew they could mine it. They had the manpower and the experience to get it out, and they looked at the chemistry and it was the chemistry that they were looking for to make this super mirror.

So Corning ordered a shipment of this so-called waste rock to be used in the Hale Telescope mirror. Alex described the process of getting the rock out of the mine for shipment.

(41 seconds) It was dangerous work, um, some of these men used steel rods with sharpened bits and they would put it up to the wall and another man would take a 10-20 pound hammer and slam that rod of steel, and then the man holding the steel would turn it a quarter-turn on each blow of the hammer. It was hard…a lot of injuries. These were mountainous mines. They would put the ore on a sled or a wagon and bring it down with mules, and there are legends of the wagons getting away and running over the mules, running over the men and just, just really hard hard tedious work.

Finally, on March 25, 1934, Corning cast the first mirror, but it was damaged due to the extreme heat needed to keep the glass molten while it was being poured. A second attempt at the casting took place in September, 1934 which was successful. Corning then shipped the mirror to California via rail car, where it was stored during World War II. It was finally polished and placed in the telescope housing in 1948. The Hale Telescope then began regular operation on January 26, 1949, when Edwin Hubble observed NGC 2261, also known as Hubble’s Variable Nebula.

Interestingly, one of the test blanks for the mirror cast by Corning was later used as the primary mirror for the 120-inch C. Donald Shane Telescope at Lick Observatory, which was the second-largest telescope in the world when it was completed in 1959. That mirror may have also been made from Spruce Pine Mining District quartz.

But back to today. The era of small family-operated mines in Spruce Pine is long-gone. Today, international corporations control the mines and their treasures, and they are still making significant contributions to astronomy, and not just through the telescopes. While we were talking, Alex pointed out that ultra-pure quartz is a key component of today’s electronic devices, from computers to televisions, cell phones, and video games. Guess where that quartz is mined exclusively in the world: right here in Spruce Pine.

(42 seconds) Today, really, the Spruce Pine quartz is the highest-purity quartz found in the world. It leads the supply to making semiconductors, which are quartz chips. The silicon is not actually derived from this quartz, but the apparatus that makes and grows the crystals comes from Spruce Pine. The crucibles, the vapor deposition cylinders, the bolts, the furniture that hold the silicon wafers…a lot of the processing steps could not happen without high-purity Spruce Pine quartz from the Spruce Pine Mining District.

(1 minute, 35 seconds) A lot of your high-intensity lighting comes from high-purity quartz…your automobile lighting…those bulbs get so hot and produce such a high amount of light. There’s extreme heat there…any impurities in the glass would cause premature failure of the glass. So, your high-intensity lighting…your street lamp lighting…automobile lamp lighting…your projector lamp lighting those kind of things…the high intensity lighting where you really need a lot of light…those bulbs come generally from quartz ore processed from Spruce Pine. Of course your semi-conductors come from there, and a lot of your glass tubing comes from here, apparatus for quartz devices comes from here and also the fiber optics, some of those systems come from here. And then you’re looking at plasma screens and lots of things in the future. The door is really wide-open for what happens from these minerals, these super high-purity minerals that aren’t found in many places in the world, and so, these are strategic minerals that are important for all of us…the feldspar of course which forms right along with the quartz makes the glass we use, the ceramics we use, the pottery we use, electrical insulators, spark plug insulators, and the list just goes on and on and on.

Today and in the future, touchscreens and solar panels are just a couple of cutting-edge technologies being supported by Spruce Pine quartz.

(29 seconds) Some of those screens will involve the quartz and especially solar panels. The more pure you have a glass system for solar panels, that’s huge. It’s just these purities are so much more efficient and it’s the lack of iron and the lack of these other impurities that make these materials so special, which is the same thing and the same reason that the Hale Telescope was produced from here.

(9 seconds) North Carolina leads the United States in the production of mica and feldspar and high purity quartz, and most of it comes from the Spruce Pine Mining District.

So the computer you use today, the cell phone you’re holding, the mp3 player you enjoy, the video games you play, the lab equipment for your work, and even the halogen headlamps on your car, in fact most electronic gadget or system in use today, along with the touchscreen panels and devices of tomorrow…all of it is made possible by the ultrapure quartz found in the Spruce Pine Mining District. I find it amazing that such a small area has made such contributions in the past and can still be so important. I hope you do too!

If you would like more information on the Hale Telescope, the Shane Telescope, the Spruce Pine Mining District, or western North Carolina, please visit my website at Again, thank you for listening.

End of podcast:

365 Days of Astronomy
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3 Responses to November 4th: The Role of Spruce Pine Quartz in Astronomy

  1. RapidEye November 4, 2011 at 8:39 am #

    Great Podcast! I live in Central NC and really enjoyed knowing the Tarheel connection to the big scopes!

  2. Bill Pittman November 19, 2011 at 8:16 pm #

    David Biddix is my nephew – I can see tne Chestnut Flat Mine from home in Ledger- We can no longer visit the mine because the land is posted.Many miners that worked in the mine died from silicosis caused the dust from the Feldspar & Quartz

  3. Eric Scholz August 3, 2012 at 1:32 pm #

    Enjoyed this very much. Thank you.

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