Rose Quartz Geode - Druzy Cabochon | What is Druzy? Druzy crystals take hundreds or even thousands of years to form. They form as molten rock begins to cool with trapped gases inside. The gases cause gaps in the rock. As groudwater flows through these gaps for century after century, minerals crystalize on the rock--forming a blanket of intense crystalization.
So it didn't work when the whole thing had a layer of soil then a layer of sand (soil rose and mixed with the sand when watered, though may work with a tiny pot with a small cactus in submerged into the bowl full of sand, the only soil being in the pot. Possibly cut the rim off to hide under sand in shallower container.
Bismuth Geode/ bismuth that has been grown and cooled in an eggshell! Apparently bismuth is one of the easiest crystals to grow yourself. Bismuth does not naturally occur in geode form. What fun to create your own dragon's egg!