The lava is pahoehoe Lava.
It is called a glaze.
Obsidian
but not
If your talking about colored pencils, put your color down on the page and go over it very hard with the white or yellow in you set, this is called garnishing.
potters can cover a ceramic with a thin layer of silicon dioxide and heat it again. This process forms a glassy waterproof coating called a glaze.
The lava is pahoehoe Lava.
Pahoehoe or pillow lava - same thing
It is called a glaze.
Obsidian.
a rock
This is called the luster of the mineral.The luster of a mineral is the way its surface reflects light. Most terms used to describe luster are self-explanatory: metallic, earthy, waxy, greasy, vitreous (glassy), adamantine (or brilliant, as in a faceted diamond).
Tektites
Obsidian
obsidian
Obsidian: Its texture is glassy. Obsidian is extrusive or volcanic, because the instantaneous cooling that produces such rocks is a surface phenomenon. Obsidian is amorphous, so, unlike true rocks, it is not composed of minerals.
Articular Cartilage
This is called the luster of the mineral.The luster of a mineral is the way its surface reflects light. Most terms used to describe luster are self-explanatory: metallic, earthy, waxy, greasy, vitreous (glassy), adamantine (or brilliant, as in a faceted diamond).