Analysis: Pink moonstone

Is pink or peach moonstone also real moonstone?

Classic ‘true’ moonstone is mineralogically a combination of orthoclase or microcline with albite (belonging to the group of alkali feldspars) with a distinct (blue) flash. But moonstone today has become more a reference to the effect of a “flash” among different feldspars, rather than a name for a specific mineral. With the increasing popularity of moonstone, the name is also given to all sorts of feldspars that sometimes do not show any form of blue ‘flash’ at all, so in my opinion they do not really live up to the name moonstone. Thus we now know black, gray, pink, peach, white, beige, green and rainbow moonstone. The exact mineralogical composition of these types is often not known but is also of no interest to most enthusiasts and sellers, moonstone is booming business….

I had two samples analyzed of different rough pieces sold as “pink moonstone,” bright pink material from Namibia and more salmon-pink pieces from Madagascar (also called peach moonstone).

left: rough “pink moonstone,” Erongo, Namibia (8 and 9 cm wide) massive grayish-white material, with bright pink spots; right: rough “pink or peach moonstone,” Madagascar (each 3 cm wide) salmon-pink with clear cleavage surfaces

Analysis pink moonstone Namibia

The first sample is a massive chunk of grayish-white mineral, with bright pink flecks, from Erongo Namibia. It has a marzipan-like structure, resembling massive quartz or quartzite. There is no obvious cleavage visible as you would expect with a feldspar. There is also no (blue) flash visible anywhere. Hardness is 6 to 6 ½, lower than quartz so and appropriate to feldspar. Chemical analysis using EDX/EDS, Raman spectroscopy and X-ray diffraction (XRD) show the composition of albite with microclines, the two endmembers of the group of alkali feldspars. This makes it mineralogically the same as “real” moonstone, however, any form of (blue) flash is totally absent. The bright pink spots, by the way, are caused by impurities of potassium.

detail image via USB microscope clearly showing the grainy marzipan-like structure of the pink moonstone from Namibia; no clear cleavage and (blue) flash is visible anywhere

Analysis pink moonstone Madagascar

The second sample is a cleavage piece of salmon pink feldspar from Madagascar, also called pink or peach moonstone. The piece has the typical feldspar cleavage, with the typical pearlescent sheen or “flash” on the cleavage surfaces. No blue flash is visible anywhere. Hardness is 6, appropriate for feldspar. Chemical analysis using EDX/EDS, Raman spectroscopy and X-ray diffraction (XRD) show the composition of microcline, an alkali feldspar, no albite was demonstrated. With this, therefore, mineralogically it is not quite the same as “real” moonstone, moreover, my pieces lack the blue flash. On the cleavage surfaces of the rough pieces and in a polished hand stone of the same material from Madagascar, more pearl luster/flash is visible, but still not blue.

detail image via USB microscope of a cleavage surface with pearly luster / ‘flash’ of the pink moonstone from Madagascar

left: cleavage surface with pearly luster / ‘flash’ of one of the analyzed pieces of pink moonstone; right: polished handstone (4.6 cm) with clear pearly luster / ‘flash’ on internal cleavage surfaces

Summary

There is no unequivocal statement that all pink moonstone is indeed “real” moonstone. The bright pink variety from Namibia is mineralogically so but does not have the external characteristics such as the typical cleavage and blue flash. The more salmon-pink or peach moonstone from Madagascar does have the cleavage and a flash, but not blue, and is thus compositionally only microcline feldspar.

Although the pure separation of the different types of moonstone may not be of interest or practicality to the general public, hopefully this information will provide more clarity about the different pink moonstones in the trade.

Analyses of rainbow moonstone, green moonstone and black moonstone are also available.

This analysis was made possible in part by donations through GoFundMe.

If you want to learn to better recognize minerals yourself based on their shape and properties, take a course at Stack of Stones and watch my videos.

This post was published on social media and the previous Stack of Stones website on Dec. 29, 2021. A summary is included in the May 2022 book “Belazeriet of niet? It will also be available through the online “Gem or Scam?” library as of September 2025.