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 reddish-brown patches and speckling on a dark background. The comparison with a pumpkin's skin is immediate, hence the name.

Peanut obsidian shows beige, pale grey or light brown clusters, often grouped in twos or threes, whose shape and colour evoke peanut shells set against black.

Both names come from Mexican quarries and are not widely available in the UK. You will find them alongside the others in my guide to the types of obsidian.

The shared secret: spherulites

Here is the piece of information almost no site gives, and it explains everything: the patches in these two varieties are spherulites.

A spherulite is a cluster of fibrous crystals arranged in rays, grown outward from a single point, like a tiny ball of down. Here is how it happens.

Obsidian is a glass: the lava cooled so quickly that its atoms never had time to organise into crystals. But that 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 progresses radiating outward from that point, forming a sphere of mineral fibres, generally feldspar and cristobalite. These crystals, unlike the surrounding glass, are opaque and pale: they appear as light patches against the black.

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

The snowflake obsidian family

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

Pumpkin, peanut and snowflake therefore form a single geological family: the spherulitic obsidians. What sets them apart is neither their nature nor how they form, but three parameters.

The colour depends on the composition of the crystals and any iron oxides present: white for pure cristobalite, beige to orange once iron gets involved. The size depends on how much time was available for growth: the slower the cooling, the more room the spherulites had to grow.

Pumpkin or peanut: how to tell them apart?

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 surface coverage: pumpkin tends towards large patches, peanut towards isolated spots.

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

The properties credited to these varieties

As with the other recently named varieties, worth saying: there is no ancient tradition specific to pumpkin or peanut obsidian. Today's correspondences were formulated by analogy with their appearance.

They are generally credited with:

• grounding and protection, qualities common to all obsidians;
• 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 are linked to the root chakra like any 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 red-brown palette with far better availability, and it is the one I work with in the workshop.

Recognising and buying

Good news: these varieties are rarely faked, simply because demand and prices are both low. The main risk is not a fake stone, but a dyed stone or a fanciful name.

• Spherulites should have a texture, in raking light, you can feel a very slight difference in level between the polished glass and the crystallised zones, which are softer and so slightly recessed;
• The edges should be soft-focus, a spherulite blends gradually into the glass. A crisp, regular outline gives away a dye or a print;
• The distribution should be irregular, patches spaced too evenly are suspect;
• Be wary of fluorescent oranges, genuine pumpkin obsidian stays within earthy tones, never garish.

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

One technical point worth knowing: since spherulites are softer than the surrounding glass, they polish less well. A stone with large spherulites often has a slightly uneven polish, that is not a manufacturing flaw, it is the nature of the material.

Mineralogical fact 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 penetrate the crystallised zones;
• Cleaning, a soft, dry cloth is preferable. If needed, a quick rinse under clear water then dry immediately;
• Cleansing, smoke works perfectly here, since it avoids any contact with liquid. Avoid salt, which lodges in the spherulites;
• Charging, moonlight, without prolonged sun exposure;
• Abrasion, never scrub with a sponge or a rough microfibre: you would wear down the spherulites faster than the glass, hollowing the polish.

The full run-through is in my guides to cleaning your obsidian and to cleansing and charging.

Frequently asked questions