Lava is a liquid molten mass that solidifies when cooled, pouring out of the vents of volcanoes. Magma, pouring out on the surface of the Earth, turns into lava. When lava cools, crystallization processes occur, due to which it can contain various minerals inside. In addition, lava may contain gas bubbles in which agates form.
You can see lava stone for sale and buy it in the Minerals of Russia online store.