Iron Out vs. Rock Quat vs. CLR on Kyanite
with iron stains and hematite
Images of the Kyanite before the Iron Out has had any effect
Well.. now I have seen iron stains (aka hematite?) on kyanite. Thanks for the photo! I had no idea such a deposit existed nor that it was mined/quarried. The only colors I've found on the eastern ridge of the Appalachins has been white, blue, and gray.
The hematite looks mainly the specular gray variety. I've recently been reading some very old journals about the injection of specular hematite into oolites within narrow veins within Silurian Red Beds (hence the article name: "Silurian-aged Red Bed Iron Deposits of the Southern Appalachians"). I have a specimen from Rockwood Tennessee which included red colored crinoid sections with flakes of silvery hematite scattered through out the matrix. The original mine is the site of a major mine accident with the miners yet entombed and the site was backfilled.
How the kyanite: formed at depth came to exist between beds of sandstone that did not get changed into quartzite is even more an enigma than the presence of the hematite. The answer for the kyanite must be that it was forced up as a plug in a pegmatite on some locally concentrated swarm of pipes. The apparent iron stain could be siderite-- iron carbonate which would take very hot acid over a period of weeks (if at all) to remove. I had suggested manganese earlier but I didn't see any black dendritic signs. Clearly the red tones are hematite maybe limonite and in the vein in the slab probably siderite. All are "secondary mineralization" to the kyanite. That is they formed long after the kyanite. The reality is one may never be able to remove the iron from the specimen--but I kinda like it as is.
Judging from the ambient color, looks like the Iron Out was more like Iron In, or maybe Iron Oxidizer!