Geodes with soil inside?

geodes soil dirt inside earth internalThese two quartz crystal geodes seemed the same, the same outside colour and material, apart from the shape. One was a good spheroid geode but the other was irregular shaped.

These were part of a Christmas present - Tobar Geodes Mining Kit - that came with 2 geodes and a rock hammer.

The round geode was cracked opened first to reveal the quartz crystals inside, as expected but still wonderful to see.

The irregular shaped geode was next and with its shape harder to split open near the middle. The side part was broken off to unexpectedly reveal soil inside the internal cavity, as well as the expected quartz crystals lining the surface of the internal structure.

tobar geodes mining kit earth science

What and how are geodes formed?

Geodes are hollow, roughly spheroid structures that occur in certain sedimentary and volcanic rocks.

They are created when crystals form in rock cavities, often within gas bubbles that occur when the rock is still in liquid state. Once the rock has hardened the cavity repeatedly fills with water that has minerals dissolved in it. Over millions of years the minerals that the water deposits within the cavity grow into crystals.

Most geodes contain quartz crystals, although other minerals can also be deposited, leading to the creation of different colours and patterns around the edge.

Quote from Earth Science Geodes Mining Kit pack

quartz crystal geode soil dirt inside cavity

Geode with internal soil?

How can a geode have dirt in the internal cavity?

Why does only one of the geodes have earth inside but not the other?

Is it because the irregular shaped geode was irregular shaped? When it was formed in its electromagnetic pinch, the growing shape of it meant that the source material in that small area was not all transmuted into the quartz crystals?

Or that the material had some oddity in that area so the transformation of it was not complete?

Or the electrical energy/discharge stopped right at the end of the this particular geode forming process, leaving some of the soil inside?