Sky blue is a kind of special lava stone, it is blue and light green, exquisite like marble plus harder than granite. Sky blue shows superiority in sgs tests and its quality reaches class a in line with gb656-2001- the criteria of building materials
As  for our glow in the dark stone,
it is man-made stone, based on material, there is plastic, resin and ceramic stone;
based on afterglow color, there is yellow-green, blue-green and sky-blue color stone.
based on shape, there is cobbles and crushed particles.
Ceramic cobbles has higher hardness and more better weather resistance.
Plastic cobbles has more daytime colors and more pieces in one kilogram, it is economic to use such product
