Glowing Secrets

 Today the museum took its various summer research program students on a field trip. That included the biology students like me! And so we hopped on the bus and jumped the state line over to the Sterling Hill Mine in New Jersey.

The mine is no longer active, but its one of the oldest mines in the country. It ran from 1646 to 1986, going out of business so recently that one of the tour guides was one of the miners. The rock is metamorphic, a sort of marble, or very compressed limestone that originally formed around hydrothermal vents, just like you can find at the bottom of the ocean today.

Its a pretty common looking cave at first, although the bats are kept out of the area that people can tour for the health of both and it is definitely manmade. But it is wet, dark, full of rock, and covered in stalactites (top!), stalagmites (bottom!) and flowstone (which runs down the walls.) All three are formed by water dripping through the walls, carrying minerals and taking roughly a week to get from the top to where they drip off the rock. When the rate of formation is well understood, core samples can be taken and oxygen isotopes (molecules of O2 that are different weights) can be used to tell whether it was a wet or dry year. Lighter weights indicate a wet year, heavier indicate a dry year. This also gets used in bones and teeth in animal fossils.

Because the cave is marble, it is really hard rock. As a result, there were parts of the mine wall that the men working in it could not access for the first two hundred years that it was worked. (Note that the hardness of the rock led to a remarkably low death rate even before labor laws went into place, though it was still significant.) Meanwhile, the lowest chambers of the mine had to be constantly pumped out at costs reaching millions of dollars a year. However, for a long time the mine was still profitable; it produced iron that was needed for common use and eventually World War II, There have also been various other resources through the years that have only ever been able to be found here.

That includes minerals that just so happen to be fluorescent. That means the chemical composition of the rocks reacts with specific wavelengths of ultraviolet light, the same waves that can burn you if you're exposed to extreme sun for too long (so don't stick your eyes under these lights! They are stronger than normal black light!!). We're not really sure exactly what about their chemical composition leads them to glow like they do; some do, while those from other mines may not. But they are impressive to look at.

See, they start out looking like this.....














And then you hit the lights and turn on a UV light....











And then someone artsy comes along....

 A little bit of history for you; Edison had a mine nearby where he found a way to separate out zinc ores, giving even higher purity's than those that are world famous for coming from the area. He spent two million dollars in the process, found that it was profitable as a result, and "had fun doing it." He also developed not just a light bulb, but also one that could be used in the mine safely. It didn't rely on a flame, and had a battery pack like your car battery that could last for up to twelve hours. This, new laws, better ways to detect dangerous gas in the air, a mechanism for men to use to breathe longer in a low air situation, better supports, and various other inventions that came with time greatly improved the safety of the job. Its not perfect, even to this day in other modern and active mines, but its better than it was.

I should mention that we had the privilege of collecting florescent minerals while we were there. Now I need to get a UV light to look at them with!