“Reflective” fireglass is only fireglass with one side metallic/mirror-coated to achieve the desired sparkle and shimmer effect. This product, made and sold by Fireplace Glass San Diego, is made of tempered glass to withstand the heat of a fireplace or fire pit flame, if properly installed. ~1/4″ means that the average size is ~1/4″. Some pieces can be quite smaller and some can be quite larger, this is typical for all kinds of fireglass. IMPORTANT: Any fireglass on the market can be used only in devices designed by the manufacturer for use with fireglass. (And if it can be used, you need to respect the recommended size of fireglass). Propane burners do not burn as clean as natural gas and can cause discoloration and sooting, so it is recommended to use dark colors with LP propane. The shade/hue of the glass can change dramatically in different sources of light as well as in different colors of surrounding areas, backgrounds, etc. The image of this glass may be distorted by the settings of your viewing screen.