BLOCKS [Glass]: Hollow, Solid

BLOCKS [Glass]: Hollow, Solid

(Wikipedia excerpt: .."...Glass brick, also known as glass block [B] , is an architectural element made from glass. The appearance of glass [B] can vary in color, size, texture and form. Glass bricks provide visual obscuration while admitting light. The modern glass [B] was developed from pre-existing prism lighting principles in the early 1900s to provide natural light in manufacturing plants. Today glass [B] are used in walls, skylights, and sidewalk lights.
...The texture and color of glass [B] can vary in order to provide a range of transparency. Patterns can be pressed into either the inner void or the outside surface of the glass when it is cooling in order to provide differing effects. Glazes or inserts may also be added in order to create a desired private or decorative effect...
Glass blocks in Europe are manufactured in accordance with the European Standard EN1052-2. The International Standard is ISO TC 160/SG1. The Standards allow for variation in sizes and production irregularity. Blocks fall within three classifications; Class 1, Class 2 and Class 3 with Class 1 being the highest and best rating with a maximum permissible deviation from designed size and rectangularity of 1 mm. Glass brick has an r value between 1.75 and 1.96, close to that of thermopane windows.[1][2] There are newer glass blocks injected with argon gas and having a layer of low-emissivity glass between the halves, which increases the insulative (U) value to 1.5 W/m2·K, which is between triple glazed windows (1.8 W/m2·K) and specialty double glazed windows with advanced frame and coatings(1.2 W/m2·K).[3]...")