Standard clear glass has a slight green tint due to iron content. If you want a perfectly crystal-clear look where the edges glow bright white instead of green, opt for low-iron glass .
The thickness of the glass directly dictates how much weight your shelf can safely hold: buy tempered glass shelves
If you just need basic rectangular or corner shelves for a bathroom or living room, sites like Amazon or big box hardware stores offer incredibly cheap pre-made floating shelf kits complete with brackets. Standard clear glass has a slight green tint