Pumpkin Obsidian and Peanut Obsidian

What are pumpkin obsidian and peanut obsidian?

These are two varieties of black obsidian characterised by rounded, pale-coloured clusters scattered through the volcanic glass.

Pumpkin obsidian shows orange to russet-brown zones and speckles on a dark background. The comparison to a pumpkin's skin is immediate, hence the name.

Peanut obsidian shows beige, light grey or pale brown clusters, often grouped in twos or threes, whose shape and tone bring to mind peanut shells resting on black.

Both names come from Mexican quarries and remain little known elsewhere. You'll find them alongside the others in my guide to obsidian varieties.

The shared secret: spherulites

Here's the piece of information almost no source gives, and it explains everything: the patches on both varieties are spherulites.

A spherulite is a cluster of fibrous crystals arranged in rays, grown from a single point, like a tiny ball of down. Here's the mechanism.

Obsidian is a glass: the lava cooled so fast its atoms never had time to organise into crystals. But this glass sits in a metastable state, it "wants" to crystallise. If the temperature stays high enough for long enough, or if a flaw offers a starting point, crystallisation begins locally.

It then grows radiating outward from that point, forming a sphere of mineral fibres, usually feldspar and cristobalite. These crystals, unlike the surrounding glass, are opaque and pale: they show up as light patches against the black.

This process is called devitrification: the glass turns back, in places, into a crystalline rock. To understand how obsidian forms, see how obsidian is formed.

The snowflake family

You already know this mechanism, even if you didn't realise it. It's exactly the one behind snowflake obsidian, whose white flowers are also cristobalite spherulites.

Pumpkin, peanut and snowflake therefore form one and the same geological family: spherulitic obsidians. What sets them apart isn't their nature or how they form, but three parameters.

Colour depends on the composition of the crystals and any iron oxides present: white for pure cristobalite, beige to orange once iron gets involved. Size depends on how long the crystals had to grow: the slower the cooling, the more time the spherulites had to develop.

Pumpkin or peanut: how to decide?

Honestly, the line is blurry and depends a lot on the seller. Two markers hold up regardless.

The first marker is colour: warm for pumpkin, neutral for peanut. The second is the area covered: pumpkin tends toward large patches, peanut toward isolated spots.

The same flow can yield both, and an in-between stone will be sold under one name or the other depending on the quarry worker's mood. As with peacock velvet, these are trade names, not mineralogical categories.

The properties credited to these varieties

Worth clarifying, as with other recently named varieties: there's no ancient tradition specific to pumpkin or peanut obsidian. The current correspondences were formulated by analogy with their appearance.

They're generally credited with:

• grounding and protection, qualities shared by every obsidian;
• warmth and comfort for pumpkin, by analogy with its autumnal tones;
• balance and patience for peanut, in line with snowflake obsidian, whose structure it shares;
• inner growth: a correspondence that follows nicely from the geology, since spherulites are literally crystals that grew within frozen matter.

As for chakras, they're linked to the root chakra like every obsidian, and pumpkin sometimes to the sacral chakra for its orange tones. The full picture is in my guide to obsidian and chakras.

If these warm tones appeal to you, mahogany obsidian offers a similar reddish-brown palette with much better availability, and it's one I actually work with in the studio.

Recognising and buying

Good news: these varieties are rarely faked, simply because they're not in high demand and aren't expensive. The main risk isn't a fake stone, but a dyed stone or a fanciful name.

• Spherulites should show relief, in raking light, you can spot a very slight difference in level between the polished glass and the crystallised zones, which are softer and sit slightly recessed;
• Edges should be diffuse, a spherulite blends gradually into the glass. A sharp, regular outline points to a dye or a print;
• Distribution should be irregular, patches that are too evenly spaced are suspect;
• Be wary of fluorescent oranges, natural pumpkin stays within earthy tones, never garish.

On price, these varieties sit among the most affordable obsidians, on par with snowflake. A high price isn't justified by rarity here. My benchmarks are in obsidian price and value.

A technical point worth knowing: since spherulites are softer than the glass, they polish less evenly. A stone with large spherulites often shows a slightly uneven polish, not a manufacturing flaw, just the nature of the material.

Mineral data sheet

Care and cleansing

One specific precaution applies here, tied to the structure: spherulites are softer and slightly more porous than the surrounding glass.

• Avoid soaking, water can seep into the crystallised zones;
• Cleaning, a soft, dry cloth is best. If needed, a quick rinse in clear water, dried immediately;
• Cleansing, smoke cleansing works perfectly, since it avoids any liquid contact. Never use salt, which lodges in the spherulites;
• Charging, moonlight, without prolonged sun exposure;
• Abrasion, never scrub with a sponge or rough microfibre: you'd wear down the spherulites faster than the glass, hollowing out the polish.

The full run-down is in my guides to cleansing and charging obsidian.

Frequently asked questions