These are small red lava rockes. Small lava rockes are porous, great to let water go thru and function as filter. They are one of the best rock to grow moss, easy to use. With a glass bottle with small lava rockes, moss can grow well.

There are two size options: 1-3mm, 5-8mm.

The 5-8mm is used as the bottom layer of a terrarium, to prevent waterlog. Above the lava layer, there are sphagna layer and soil. Please check my attached terrariums, the bottom layer, they are the smal lava rockes.

With those small lava rocks layers at bottom of the glass terrarium, you will see immediately if you over water your plants. It allows you pour out the extra water easily. putting in small lava rockes is the beginning steps of almost every moss terrarium and succulents terrariums I made.

The 1-3mm smaller size usually functions as decorative rock in the water. It has a suitable size to make your waterpond decent.

In my waterpond terrariums, I put the 1-3mm lava rockes at bottom to let the large rockes stand stable and adjust its position.

There are two color options: red lava and black lava. This is the red one, there is a red one in my shop too.

Ideal for plants like orchids, succulents, cacti, and bonsai trees

Size: 1-3mm, 5-8mm
Weight: 700g/ 1.54lb