Black Moonstone

Black Moonstone is a dark-bodied variety of moonstone, a feldspar gem known for adularescence, the soft billowy glow that seems to float beneath the surface. Where classic moonstone is pale, black moonstone has a smoky gray to nearly black base that contrasts dramatically with its blue, silver, or white sheen.

Much black moonstone is a feldspar in the plagioclase to alkali range and commonly comes from Madagascar. It often shows subtle flashes and sometimes peach or rainbow tints alongside the dominant blue.

The adularescence arises from light scattering off microscopic intergrowths of two feldspar phases, the same mechanism behind ordinary moonstone, simply set against a darker background that makes the glow especially striking.

Black Moonstone forms as feldspar crystallizing in igneous rocks such as pegmatites and related intrusions. As the crystal cools slowly, two feldspar compositions unmix into alternating microscopic layers (exsolution lamellae); light scattering from these layers produces the adularescent sheen.

The dark body color comes from fine inclusions or compositional features within the feldspar. Much commercial black moonstone is sourced from Madagascar, with other feldspar moonstones coming from India, Sri Lanka, and elsewhere. The interplay of a dark host and reflective internal layering is what distinguishes black moonstone from its lighter counterparts, and the effect is enhanced by careful cutting that orients the sheen.

Black Moonstone is a feldspar of Mohs 6-6.5 with two good cleavages near 90 degrees and a vitreous to pearly luster. Its hallmark is a dark gray-to-black body that shows a soft blue, silver, or white adularescent glow that shifts as the stone is tilted.

The sheen is a billowy, floating light rather than the spectral flash of labradorite or the sparkle of sunstone. Streak is white.

Distinguish it from black labradorite/spectrolite (which flashes broad spectral colors) and from black onyx or obsidian (which lack adularescence and have different hardness and no feldspar cleavage). Dyed or glass imitations lack the genuine internal billowy glow.

Black Moonstone is used primarily as a gemstone, cut into cabochons, beads, and freeform shapes for rings, pendants, and earrings. The dark body makes the blue and silver sheen pop, and it has become popular in artisan and bohemian-style jewelry.

Value depends on the strength and color of the adularescence and the evenness of the body color. Because it is a feldspar with cleavage, protective settings and gentle care help preserve it.

In metaphysical traditions black moonstone is associated with new beginnings, intuition, and feminine energy, often linked to the new moon; these are traditional beliefs rather than scientifically demonstrated properties.