Specimen #564

Name: Goethite

Type: Mineral

Locality: Dachang mine, Qinglong County, Guizhou Province, China

Favorite? N

Fluorescent? N

Size: 11.2x2.2x2.0 cm

Weight: 68

Acquired: 2008-03-01

Source: Trinity: Andrei Rykoff

Label: N

Comment: This is one unusual piece, in my estimation. It comes from a new find in China. It's either a stalactite or stalagmite. I'd vote for stalactite, but you can't really tell. Goethite is commonly found in iron ore deposits and up until now, I had never seen it in this form. It varies in color from a dull metallic look to very iridescent. This is a very unusual and attractive mineral specimen. No damage! I queried dealer if it was a fake. His response: First of all, it is Chinese, and there can always be a problem! I did not suspect anything, and the price structure did not suggest taking the time/effort to fake. The flaking nature is natural/logical for any stalactitic/stagmitic growth, so I don't see that as an issue. A wire in the center would certainly be an issue though. Doesn't mean it is faked, but could be natural growth in a modern environment. Copper would be a natural nucleus for malachite growth, but not really for FeOx. A steel wire would be more appropriate. I did not see any such thing, so you might want to look at the other 2 pieces. My gut feeling is the super dense, well indurated nature of the oxide with the pearlescence would be quite difficult to manufacture. Looks like something that took a long time to form. That's about all I can say other than I looked at them semi-closely when I got them just because I had never seen anything like them before. I didn't see anything to suggest they were fake. Obviously, if they are fake, I'll take them back. There is a picture of similar goethite in the book "Fine Minerals of China" p. 121.

Minerals: Goethite (Fe+++O(OH))

There are 5 pictures on file