That's actually my old frock coat! Bill is right, it is one of three coats made for the Randolph Mess by Jim Ruley, a very talented self-trained tailor who is well versed in mid-19th Century garment patterning and construction. The fabric is Family Heirloom Weaver's very first run of dark green cloth....yes, it does turn orange for some people who sweat on it. I was told that the color-changing properties are based on a person's pH balance but if any of the cloth does happen to turn orange then a spot-rinse in pretty much any bar soap will turn it back.
However......I did try to prevent this from happening to me by eventually top-dying the entire coat (except sleeve linings). The collar was also lowered by me and a dark green kersey inner collar replaced the older worn one.
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Brian WhiteWambaugh, White, & Companyhttp://www.wwandcompany.com----------------------------------
Randolph Mess, U.S. Sharpshooters