The Lamp is a decorative light source block. To it turn on, it must either be placed on a Bedside Cabinet or be powered by redstone.
When a Lamp is turned on while placed on a Bedside Cabinet, it will send out redstone signals from all sides of the bedside cabinet and underneath the cabinet also. This could not be used to make a secret door as such.
The textures the lamps uses are white wool to represent the lamp shade and obsidian for the stand.
The Lamp can be made using the image below as a guide. It requires 5 White Wool, 1 Glowstone and 1 Obsidian. Place 3 white wool across the top, one on the middle left and right, glowstone in the exact middle, and obsidian on the bottom middle. The recipe makes you 2 lamps