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Gemini gave me lots of info on what I thought was a great lookin' rock.
When [Indian Tunnel]() was a functioning river of molten lava, the intense heat melted the "ceiling" of the tube. As the lava level dropped, the semi-molten rock on the ceiling began to drip downward. These drips cooled mid-air, creating the small, bumpy protrusions (stalactites) covering the surface.
### 2. Why it's on the Floor
This rock is a piece of **"breakdown."** Over thousands of years, after the lava finished flowing and the cave cooled, the expansion and contraction of the rock (and potentially earthquakes) caused sections of the ceiling to collapse. This specific block fell from the roof, flipping over to reveal the "dripped" texture that used to face downward.
The tiny holes throughout the rock are **vesicles**. These were gas bubbles trapped in the lava as it solidified.
* **Mineral Coating:** The white or silver-grey sheen on the surface is often a combination of **volcanic glass** and secondary mineral deposits (like caliche or silica) that have leached from the surrounding rock over centuries of water dripping through the cave roof.
When [Indian Tunnel]() was a functioning river of molten lava, the intense heat melted the "ceiling" of the tube. As the lava level dropped, the semi-molten rock on the ceiling began to drip downward. These drips cooled mid-air, creating the small, bumpy protrusions (stalactites) covering the surface.
### 2. Why it's on the Floor
This rock is a piece of **"breakdown."** Over thousands of years, after the lava finished flowing and the cave cooled, the expansion and contraction of the rock (and potentially earthquakes) caused sections of the ceiling to collapse. This specific block fell from the roof, flipping over to reveal the "dripped" texture that used to face downward.
The tiny holes throughout the rock are **vesicles**. These were gas bubbles trapped in the lava as it solidified.
* **Mineral Coating:** The white or silver-grey sheen on the surface is often a combination of **volcanic glass** and secondary mineral deposits (like caliche or silica) that have leached from the surrounding rock over centuries of water dripping through the cave roof.