Sunday, June 29, 2008


Recently, I was fortunate to visit the Stewart Lithia Mine in Pala, California with an academic group from the Gemological Institute of America (GIA). As a current student at the GIA, this was a very exciting opportunity to visit a working mine not open to the public and to listen to Blue Sheppard (the mine owner) recount his discoveries!

Located in north San Diego County, the area is rich in pegmatite. A pegmatite is a coarse grained igneous rock (formed deep within the earth) having a grain size of 3cm or more and composed of granite and its constituents like quartz, feldspar and mica. The Stewart Lithia Mine was originally mined to extract lepidolite, as the lithium it contained (about 5%) was refined and used for ceramic glazes, to color flares, and for grease. Lepidolite ore is a beautiful conglomerate of lilac, lavender and pink and seemed pretty soft to me. Additionally, it contains bits of pink tourmaline crystals!

Tourmaline (Mohs 7.253) is harder than quartz and produces gorgeous gemstones when cut. It comes in a variety of colors including pink, green, blue, black, etc. Most of the pink tourmaline that was mined at the Stewart Mine went to the empress of the Ch'ing Dynasty Imperial Court and her entourage, who purchased everything they could get in order to have it exported to China. Gem quality natural pink tourmaline is five times as rare as gem diamond and more than ten times as valuable as gold in its pure form.

In the tunnels, Blue explained to the group how he learned to “read” the rocks and understand where to look for tourmalines. In addition to touring the underground tunnels of the mine and seeing the sites where some of the largest and most beautiful tourmalines were discovered we were allowed a few hours to search the ground and tailings around the mine. It was a beautiful day, having cleared up from the previous two days of hard rain. That rain definitely gave us an advantage by washing away some of the loose dirt and exposing the heavier minerals. I was able to pick up several fairly good size pieces of pink tourmaline that were laying right on top of the soil, and on careful examination of the walls of tailing piles I could see the crystalline shape that I was looking for and simply pull the tourmalines out. That's me in the center in a pale pink top.

I found several small pink, green, a pale blue, and even a bi-color. But, try to imagine my excitement when I saw the flat end of largest one (center in my photo) and kept pulling as this beautiful 26.7 carat dark pink tourmaline measuring 1" long x 1/2" wide x 3/8" thick emerged from the sandy soil!

I showed it to Blue and he held it up for the rest of the group to admire…and within minutes my little area was full of eager “miners” hoping to find something similar. A few visitors found beautiful tourmalines that day, and one person found a pretty kunzite.

I hope to find a cutter who will be able to carefully fashion the large one into a gemstone, but in the meantime I enjoy looking at this pretty collection every day.

It was a fabulous trip and I learned so much!

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