Aegirine

Aegirine is a sodium iron silicate pyroxene mineral with the formula NaFeSi2O6.

A good crystal shows its character quickly. The prisms are long and sharp-edged, even within a cluster, giving a blade-like form. When turned under a lamp, the luster shifts from inky black to bottle-green. Most pieces are opaque, but very thin tips can appear green at the edge, producing a faint glowing line.

Aegirine is often mistaken at first glance for black tourmaline or hornblende. It usually has cleaner, glassier crystal faces and grows as straight, striated prisms rather than the rounder, furrowed habit of tourmaline. The best cabinet specimens have crisp terminations that reflect light like small mirrors. The mineral is not especially tough, and the tips chip more easily than expected.

Aegirine first got described in 1835, by the Swedish mineralogist Jöns Jacob Berzelius. Its name comes from Ægir, the Norse sea god, since the original material was from the Låven (Låven island) area near Brevik, Norway.

Older books sometimes call it "acmite," and that name still appears on vintage labels and old dealer cards. In modern mineralogy, "aegirine" is the standard term, especially for the darker green to black crystals that collectors seek.

It turns up where alkaline igneous rocks are doing their thing, plus some metamorphic settings. Classic collector localities include Norway’s larvikite area and Mont Saint-Hilaire in Canada.

Most aegirine forms in silica-undersaturated, sodium-rich igneous settings, including nepheline syenites, alkaline granites and pegmatites. These rocks have a chemistry quite different from ordinary granite. When the melt is rich in sodium and iron, aegirine is one of the pyroxenes that can crystallize as long, slender prisms.

Look at the matrix on a lot of specimens and you’ll catch it sitting right next to feldspars, nepheline, sodalite, eudialyte, plus other alkaline-suite minerals. Sometimes you can even spot it threaded through the host rock as those dark green to near-black needles, especially when it’s wedged between lighter grains (it really jumps out). And yes, it can form during metamorphism too, mainly where sodium metasomatism has messed with the rock’s chemistry. But if you’re talking about the crisp, showy crystals people actually chase, those are usually igneous-grown and nicely formed.

Color: Most aegirine is black to very dark green; thin edges can show a clearer green when backlit. Some pieces look almost brown-black until you hit them with strong light.

Luster: Vitreous, often with bright reflections on clean crystal faces.

Pick up the piece and tilt it slowly under a single light source. Aegirine will often flash green along edges even when the body looks black. If you scratch it with a steel nail, it usually won’t gouge deeply, but it can show a faint mark because it sits around Mohs 5.5 to 6. The real test is the crystal habit: straight, prismatic “blades” with fine lengthwise striations are a common giveaway compared to chunkier black amphiboles.

Aegirine is sometimes confused with these materials:

• Augite
• Jadeite (especially dark green)
• Hornblende
• Black Tourmaline (Schorl)
• Epidote
• Dyed quartz (marketed as 'green obsidian')

Handling it is fine. But if you start cutting, grinding, or going at it hard with a brush, it can kick up that super fine dust you really don’t want in your lungs. So treat it like any other silicate mineral when you’re working with it.

If you’re cutting or cleaning with power tools, don’t do it dry. Use water to keep the dust down, make sure there’s real ventilation (like a fan actually moving air, not just a cracked window), and wear a proper respirator that seals to your face. For everyday cleaning, skip the wire brush. Go easy instead.

Rough/Tumbled: $10 - $250 per specimen

Cut/Polished: $20 - $150 per carat

Price varies widely with locality, crystal sharpness and whether the terminations are intact. The most valued material is clean, bright, needle-like crystals on a contrasting matrix, where the points catch the light when tilted. Chipped shards generally bring lower prices.

Moderate — Scratch resistance: Fair, Toughness: Fair

It’s generally stable in normal room conditions, but edges and terminations chip if it rattles around in a box.

Use & Storage

Store specimens in a padded box or wrapped, especially when the crystals are long and thin. The tips snap easily when they knock against harder minerals such as quartz.

Cleaning

1) Rinse briefly in lukewarm water to remove loose dust. 2) Use a soft toothbrush with a drop of mild dish soap, then rinse well. 3) Pat dry and let it air-dry fully before putting it back in a closed box.

Cleanse & Charge

For energy-style care, simple methods such as smoke, sound, or a quick rinse and dry are suitable. Salt soaks are best avoided, since they can leave crust in cracks on matrix.

Placement

Put it somewhere it won’t get bumped, like a cabinet shelf. Under a single spotlight it looks great because the faces throw back sharp flashes.

Caution

Skip ultrasonic cleaners and strong acids. They can chew up the matrix minerals and even wiggle loose those fragile little crystals (especially the ones that already feel a bit shaky if you tap the piece). And don’t toss it in a tumbler unless you’re genuinely fine with the sharp edges getting rounded off.

In crystal traditions, aegirine is treated as a clearing and grounding stone. Practitioners associate it with the Root and Heart chakras and with the zodiac signs Scorpio and Capricorn, and they link it with the elements Earth and Storm. Its dense, dark green-black look is often cited as the reason for the grounding association, and it is commonly described as a stone for boundaries and for setting aside unwanted thoughts.

People who use it this way usually keep a small blade in a pocket or on a desk as a reminder to focus on one task. Some pair it with calmer stones such as smoky quartz or labradorite, and some avoid keeping it by the bed because they consider its energy too stimulating for rest. These are beliefs and personal habits, not proven effects, and aegirine is not a substitute for medical or mental health care.

In practical terms, aegirine is valued mainly by mineral collectors. Sharp, lustrous crystals on a contrasting matrix make attractive cabinet specimens, and faceted material is occasionally cut for collectors. Its name honors Ægir, the Norse sea god, and the mineral was first described in 1835 by Jöns Jacob Berzelius from material found near Brevik, Norway.