On our outing to Penfield Quarry on Saturday we found some pieces of fluorite. A few of the people there said it would glow under a black light. Cool! I used to have black lights when I was a kid, along with the various fuzzy black light posters. I might even have a black light bulb still packed away somewhere, but if I do, I don’t know where it would be.
So I headed out yesterday to buy a black light bulb. I stopped in a Home Depot. They had a 24″ black light bulb, and an 18 inch black light bulb. They were not cheap either. I think the 18 inch bulb was like $12 maybe. Not sure. I looked for a portable fixture that could be plugged into a wall, but didn’t find one, and I didn’t have a lot of time. I looked around some more, and found a 75 watt incadescent black light bulb. And it was only $4. So I bought it and headed out.
When I got home last night, I screwed it into a lamp, and turned it on. I held the fluorite and other rocks under the dim light, and they didn’t seem to noticibly glow at all. We turned off the lights, and still nothing. It was still somewhat light, so we waited till after dark. Again, no glow. Hmmmm…
We thought the light might be too dim, or maybe the incadescent light has the frequency or something.
Today at lunch, I stopped at Lowes. I found the 24 and 18 inch black light bulbs. The 18 bulb was only $9 here. I went in search of a fixture and found them. I found some fluorescent fixtures the plug into the wall. I found one that would fit the 18 inch bulb for $17. But then my buddy whow as with me found a fixture that already came with a black light bulb! We could find the price. But when I took it to the check out, it was only $20. Nice! I bought it.
When I go back to work I searched for information about black lights and rocks. I was surprised to learn there are different black lights. Long wave (UV-A), medium wave (UV-B), and short wave (UV-C). It seems that the black light I bought is likely to be a long wave. And that what I need to make the rocks glow is a short wave black light. A mid wave black light is what they use on CSI to make bodily fluids glow. Hmmm. I did a search of short wave black lights and found they are expensive. Ouch! I will try the light I bought, and if it doesn’t do much, maybe I will return it. Or maybe I will keep it. Maybe long wave black light will work on different rocks. I will have to do more research.
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Added-
I tried the black light when I got home. Unfortunatly the fluorite didn’t glow. It had a slight pruple color to it, but then everything had a slight purple color to it under the light. I think we will need to get a short wave, or medium wave black light. I will comtinue to do reasearch and see if I can find one of these for a reasonable price. I just can’t justify spending hundreds of dollars on a light just to see the rocks glow. There is always the possibility that what we have is not fluorite and the geology students that identified it as fluorite were wrong.
We did get some reaction with the black light from some other rocks. A couple rocks that had a bunch of dolomite on them, had some spots of a dim yellow glow. When we turned the lights on, we didn’t see anything different in those spots.
I have known about the Penfield Quarry for a long time, and have always wanted to visit it. Even before I got into rockhounding. Ellison Park, a local park that I have hiked many times, borders on the quarry, and I always wanted to go explore it. But I haven’t wanted to trespass on private property.
My wife and I joined a local rock club, and they had a field trip to the Penfield Quarry today. I had loaded most of the stuff in the car last night. We had to be at the quarry at 6:45am. I set my alarm for 5:15, and was awake before it went off. I get up, and vegged for a while and then got dressed, and finished loading the car. I brought all the tools I thought I might need. Basically the same kind of stuff I took to dig for Herkimer Diamonds. Sledges, bullpoint chisel, crack hammers, screens, pick axe, wedges, etc. I also packed our new hard hats. And we both wore our new steel toed boots.
We arrived at the quarry a little after 6:30 and there were a bunch of people already there. We hung out by our car, not sure what to do. Eventually we saw people heading inside the building, so we followed them. We signed a release form. Then it was time to head down into the quarry. We headed back to our car, and followed the line of cars to the area with filled with boulders.
We donned our hardhats, and headed to look at the boulders. We weren’t sure what to do, so we watched other people. I knew we were after fluorite, but I wasn’t sure what I was looking for. I had seen pictures in my books, but that didn’t help. I asked a couple guys, and they said the fluorite was in vugs. Okay. So we got our tools, and started busting rock. I was splitting open cracks. We pretty much only found dolomite, these little white crystals. We moved to a different area, and were busting on some rocks. I found a big rock that was already cracked. I worked at splitting it open more to see what was inside. More dolomite and calcite. I managed to tear some skin off of one of my fingers, and came close to breaking one of my legs when the rock I was standing on moved. Oh the fun of it!
Someone found something and everyone got excited. I went down to look at it was a tiny crystal that sort of looked like a short brown pine needle. Apparently it is rare.
We also found some selenite which was kind of cool looking. I found a big yellowish cystal on top of some dolomite as well as some tiny clear crystals. I showed them to a couple other guys who looked like they knew what they were doing. these turned out to be calcite. It looked different than the calcite we found at the herkimer mines. Then we found a tiny brown crystal mixed in with dolomite. I showed it to one of the geology students, and he told me what it was. I thought it started with “sph” and ended with “ite”. Not sure. I looked in my books when I got home. Maybe he said it was a Sphalerite. We found another one as well.
Then I found a piece covered with dolomite, and a tiny speck of purple. It almost looked like an amethyst. I showed it to the geology student and he said it was fluorite and got all excited at this tiny bit. I commented that I thought that it would be larger. I showed him where I thought I got it, and he asked if he could work the rock. I told him go ahead. He worked it for a bit, then moved on.
We kept working at vugs and breaking rocks. A little while later, I found part of a crystal with some blue in it. This was larger. I showed it to another guy and he said it was fluorite. I went back and found there was more under where I found the piece. I set about with the crack hammer and bullpoint chisel to break away the rock around the fluorite. It was tough. I didn’t want to destroy the flourite. I worked my way in towards the fluorite. The big piece of fluorite was already broken into smaller pieces, and I started pulling out the pieces. We collected a handfull of fluorite pieces. We showed them to the college student. He and his friends ooohed and ahhed over the pieces. I showed them where I got it. There was still a little bit left showing. I let them have the rock. He and he friends went to work trying to break it apart.
My wife and I were hungry and tired, so we headed home. We will probably try to come back next time they let people in. It was kind of fun.