Good day all.
I happened on a road side coal loading station, in the Swatara Gap area of NEPA last summer. Since we were four rock hounds out for a day of fossil collecting, we decided to have our photo's taken in front of the "antique" structure.
While exploring a bit (I collect odd and iridescent Anthracite) I happened on a "stripe" of bright, solidly iridescent blue coal. Clearly NOT paint, or applied, but through and through. It laid in the form of a "river", coming down from one corner of the structure of metal and wood, and widening as it descended some 3-4" to grade level. It seemed to only be the top/surface area, not the underlying, or nearby piles. I gathered as many samples as were to be had, eagerly, since this is the only time I've found it in blue.
I've read the thread, but am searching for scientific data on what causes iridescence, and any other colors. Also, I would love to have contact with those who might have other color samples to share.
Thanks in advance,