Come with me to the world’s largest sapphire mining operation (not open to the public)
Thanks to Parle Gems for the once in a lifetime opportunity visiting this mining facility.
The Rock Creek sapphire deposit is located near Philipsburg, Montana, a quaint historic town with a population of about 500.
This area has been mined for sapphires and gold since the early 1900s and you can still see the log cabins in which these early miners stayed when you first drive into the area (pictured above).
I got an exclusive look at the mining operation owned by Potentate Mining, which was first acquired in 2014, and got to see not only the giant machinery, but the offsite sorting facility as well!
The equipment used is quite loud and colossal…upon first seeing everything I realized I had no idea what goes into mining for gemstones. There are excavators that dig deep to grab all the sapphire rich layers, which first need to be separated by size, most importantly getting the big boulders separated from the rest so they don’t potentially crack sapphires or hurt the machinery. There are jigs that vibrate and mimic the sifting process a human can do with a screen and running water, but obviously on a whole new level of efficiency. The clay and gravel of the area are really thick and this part of the process is very important. Whatever material that is left after all the sorting, cleaning and separating is then brought to the processing facility.
Sieves are used to separate gravel by size at the processing facility – I’m not exactly sure on exact sizes that everything was divided into, but it seemed like there were three categories: small, medium and large. The biggest size was easiest to sort through by hand and having all the same sized gravel helps the process to go faster since your eyes are adjusted to seeing all of the same size. If you’re hoping to find “a big one” this batch is where it will be found! One of the workers mentioned that there is typically one “big one” per mining season. We got a chance to sort through some fresh batches that were never sorted before, and I was shocked at how many sapphires were found within each batch.
From here, the sapphires that were separated from the gravel will then be sorted, with the next steps either being acid-washed and heat treated or left alone. The key millimeter being 3.5mm or larger which is what they consider sellable. The sapphires produced are a variety of colors in their natural state with approximately 12% of the sapphires occurring in fancy colors. Heat treatment technology results in about 80% of the sapphires becoming market desirable colors.
I hope you enjoyed this inside look at the US’s very own Montana Sapphire mining facility. These Rock Creek Sapphires are truly special as they come from one of the most beautiful landscapes I’ve ever encountered – both tranquil and rugged, with the freshest air. I’ll be launching a special collection of jewelry using sapphires from this exact mine coming soon, in time for the holidays. Stay tuned!
All photos shot by Lauren Newman for Gem Gossip.