Yellow-fluorescent phantoms in amethyst: Is it really powellite?
For several years now, the mineral trade has been offering light-colored amethyst crystals from Brazil that show striking yellow to yellow-orange phantoms under UV light.…
Controversy surrounding purple fluorite on quartz from China
Since the publication of the first version of this article on Jan. 6, 2026, much new information has become available in a short period of…
Batu Pasir Intan (“diamond sandstone”)
Local name for an unusual sandstone that appeared on the Dutch market in 2024 through a seller with connections in Indonesia. The name literally means…
Analysis: apatite in cleavelandite or not?
By now there are a lot of stones on the market with blue spots, under a lot of different names. One name that has recently…
Analysis: Siberian blue quartz
Siberian blue quartz turns out to be ordinary glass! In July 2021, I had a piece of “Siberian blue quartz” analyzed in a laboratory to…
Analysis: Nuummite
Find out all about Greenland nuummite and similar rocks! Learn how to recognize real nuummite and how to distinguish lookalikes from China and India. …
Sphalerite or not? Part II
In my earlier article sphalerite or not? Part I you could read, which I told about some polished towers of “sphalerite” that I analyzed for…
Analysis: Black moonstone
Is ‘black moonstone’ real moonstone? Classic ‘true’ moonstone is mineralogically a combination of orthoclase or microcline with albite (belonging to the group of alkali feldspars),…
Sphalerite or not? Part I
Quite some time ago I received from one of my students who also sells stones a number of polished towers of “sphalerite.” At least under…
Analysis: White moonstone
What is white moonstone? There are several different “white” moonstones on the market, which can be, for example, a “real” alkali feldspar moonstone, an albite…
