Magnet Cove, Arkansas
1990s Old Stock
ex Henry Delinde
A bit about Tinguaite, from Mindat: "A variety of phonolite consisting of alkali feldspar, nepheline with or without other foids, aegerine and sometimes biotite. It is characterized by "tinguaitic texture" in which needles of aegirine occur interstitially in a mosaic of alkali feldspar and foids."
This is a very unique / special specimen for Magnet Cove/Arkansas mineral collectors, mined by Henry Delinde from what he has labeled as coming from "Sec. 29, Near Magnet Cove, Ark. 2/92"
So, coming from unlabeled locale, in Section 29, near Magnet Cove Arkansas (in Hot Spring County), February, 1992.
Henry took the extracted sample and cut/polished it to reveal its beautiful and unique interior.
When the specimen is exposed to Longwave UV light, a bright reddish orange flouresent mineral can be seen included in the sample. Other unknown hues can be seen as well. A Magnet Cove expert examined some of the other yellowish hues, and could not decipher what minerals they were.
I believe this reddish orange though is Magnet Cove Hackmanite, which is said to deliver some very peculiar qualities!
Here is a snippet from American Mineralogist, from JULY 01, 1941
written by Hugh Miser and Jewell Glass
"Two varieties of fluorescent sodalite are found in the tinguaite rocks of Magnet Cove, Arkansas: a blue sodalite that fluoresces a purplish-blue to violet-red, and a white variety, hackmanite, which strongly fluoresces a reddish-orange. The hackmanite also exhibits the peculiar phenomenon of evanescence; that is, change of color from rose to colorless and back again with alternate exposures to light and darkness. It shows also the property of photosensitivity; that is, the phenomenon of induced reappearance of the rose color by exposure to ultra-violet radiation and the disappearance of the color in daylight."
When we acquired this portion of Henry's collection, we found within it less than a dozen samples of this tinguaite, each ooak....Magnet Cove public collecting is no longer allowed, and the exact origin of these specimens is a mystery. So when these are gone, they are gone likely forever until the exact site is discovered again and opened to the public. This is likely to never happen. The Magnet Cove area of Hot Spring County, Arkansas is a very important area for the United States mineralogically.
8 x 5.5 x 3.5 cm