Lava rock, scoria, stones, aquarium, terrarium, gardening

My grandfather collected various stones as a hobby.
This is a set of 4 porous stones.
The descriptions found through image search are shown in images 14, 15, and 16.

I am not knowledgeable about stones, so I cannot guarantee if they are truly lava rocks.

They were in the garden, so they have dirt and other debris attached.
I lightly washed them before taking photos, so the pictures show them when wet. When dry, the reddish colors will become more subdued and muted, and the black colors will lose some saturation.

If you are okay with this, please consider purchasing. m(_ _)m

I plan to list other stones as well.
If you purchase multiple items together (まとめ買い), I can offer a discount on shipping, so please leave a comment. (If someone else purchases an item while we are discussing a bundle, the transaction will proceed as is. If you are concerned about this risk, I apologize, but purchasing multiple items together may not be feasible.)