There are two types of clear building blocks available in the market: one is glass manufactured product and the other is a crystal clear acrylic. The acrylic block is lightweight and virtually indestructible.  There are advantages and disadvantages to both glass and acrylic, but both offer tremendous creative opportunities. 

In a kitchen you can use glass blocks for custom islands, highlighted with colored lights, produces a backlit wall perfect for evening dining.  The different styles and shapes of glass block allow for building shelves and recesses.  With proper planning glass blocks can be used as a backsplash between cabinets and countertop providing light throughout the kitchen but especially on the countertop.

Bathrooms and kitchens are probably the most common location to find glass blocks, however with the flexibility of the product glass blocks are appearing in every room in the home.  In a bathroom, glass block provides a very contemporary stall shower, easy to clean and never dark.  It can be conveniently used for bathroom windows providing both privacy and a source of light.  For aesthetic value glass blocks can be used as a skirt around a whirlpool or spa tub.

By placing a metal cap and a wood cover on top of the glass block it can be a half wall or provide a guardrail on a balcony or landing.

A common location for glass block is side panels on a door.  It provides privacy, daylight on the foyer during the day and outside house illumination at night.  Glass block is as secure, if not more secure than a basic window. 

If you are a do-it-yourself individual, you should be aware that working with glass and acrylic blocks requires a certain level of skill, the same skills as laying bricks or concrete blocks.  Most manufacturers have accessories to help lay block level and plumb, but as with stacking any building material experience goes a long way in producing a quality finished product.