Stones4 min read

The holes in lava stone are gas bubbles

Cooling lava traps gas in thousands of tiny bubbles. That’s why your bracelet drinks a drop of oil and holds it for hours.

Illustration: a drop of oil falling onto a lava stone bracelet, with a cooling lava flow behind

Open a bottle of sparkling water. While the cap was on, the gas stayed dissolved in the liquid; the moment the pressure drops, it escapes as bubbles. Magma does the same. As it rises towards the surface, its dissolved gases come out as bubbles, and if the lava cools before they can get away, they stay sealed inside the rock. The tiny holes in the beads of your bracelet are exactly that: a volcano’s gas bubbles, frozen in stone.

From volcano to wrist

The lava that pours in glowing rivers down the volcanoes of Hawaii cools into basalt: a rock low in silica and rich in iron and magnesium. It runs more freely than silica-rich lavas, which is why it travels in long flows instead of piling up. The US Geological Survey defines basalt as dark by nature, from grey to black. The reason is its minerals: those rich in iron and magnesium, such as pyroxene and olivine, are dark, and their presence darkens the whole rock.

The lava stone in bracelets is volcanic rock of this kind: black or charcoal grey, light in the hand, rough to the touch and full of pinholes. Each bead is a fragment of that rock, rounded and drilled for the cord.

Vesicles: the gas that didn’t make it out

Geologists call those holes vesicles, and a rock full of them ‘vesicular’. Deep down, pressure keeps the gases dissolved in the magma, like the capped bottle. As it rises and the pressure falls, the gases form bubbles. If the lava cools quickly, it turns solid before the bubbles reach the surface and traps them: every pinhole is the cast of a bubble. When the bubbles are countless you get scoria, which the USGS glossary describes as magma ‘frothed up’ by escaping gases.

Did you know

In the tallest lava fountains of Kīlauea, in Hawaii, the bubbles grow so crowded that almost all their walls burst. The result is reticulite, a honeycomb froth of volcanic glass that the wind can carry for miles: of all the fragments a volcano throws out, it is the least dense. And yet it doesn’t float. Its bubbles are open and connected, so water gets in, fills it and sends it to the bottom.

Why it drinks oil

That same principle is what makes your bracelet work. The vesicles that open at the surface, and the ones linked to them, act as tiny reservoirs: a drop of oil seeps in and stays there, sheltered, instead of running off as it would on a smooth stone. From there it evaporates slowly, and the bead holds its scent for hours. When the scent fades, another drop is all it takes.

Every pinhole in lava stone is the cast of a volcanic bubble. A drop of oil finds a home there.

How to scent it

  1. Choose your oil. Ideally a blend already diluted in a carrier oil, the kind made for skin. If you use a pure essential oil, one drop is enough, and it goes on the stone only.
  2. Take the bracelet off and lay it on a saucer. Put one or two drops on the lava beads, not on the charm and not on the elastic: metal absorbs nothing, so the oil would sit on the surface, ready to end up on your skin.
  3. Let it soak in. Wait a few minutes, until the beads feel dry to the touch, before you put it on. That way the oil stays in the stone, not on your wrist or your clothes.
  4. If your skin reddens, take it off and wash the area with soap and water. If you’re pregnant, scenting a child’s bracelet or have sensitive skin, ask a doctor or a qualified aromatherapist first.

Never put undiluted essential oils on your skin. Keep them away from your eyes and out of the reach of children.

A breath from your wrist

In crystal lore, lava stone is a grounding stone: born of the earth’s fire, it’s worn to keep your feet on the ground. Try this. In the morning, before you head out, choose an oil and give it a simple intention: calm, focus, courage. Put the drop on a bead and let it soak in. During the day, when everything speeds up, bring your wrist close to your face and take three slow breaths. The scent takes you back to that morning moment, and to the word you chose.

Care

Take it off before the shower, the sea or the pool, to protect the metal charm and the elastic. To change the scent there’s no need to wash it: leave it out on a saucer for a few days and the old oil slowly evaporates. If you’re in a hurry, wipe the beads with a barely damp cloth and let it dry thoroughly before the new drop. Roll it on and off over your hand rather than stretching it, because the elastic is the most delicate part, and when you’re not wearing it, lay it flat.

Try it at home

Sources

  1. U.S. Geological Survey, ‘Find-A-Feature: Vesicles’.
  2. U.S. Geological Survey, Volcano Hazards Program glossary, entries ‘Basalt’ and ‘Scoria’.
  3. Encyclopaedia Britannica, ‘Basalt’ and ‘Mafic rock’.
  4. U.S. Geological Survey, Eruptions of Hawaiian Volcanoes: Past, Present, and Future, on reticulite.
  5. Wikipedia, ‘Vesicular texture’.
  6. National Center for Complementary and Integrative Health (NIH), ‘Aromatherapy’; National Association for Holistic Aromatherapy, ‘Safety Information’.