|This article is about an older version of DF.|
Glass is a material that items can be made of, like stone or wood. But although a material, "glass" as such does not appear in a pre-processed form like other materials can, such as wood logs or mined stones - the game only knows finished products made of glass, and also "raw glass", which functions like an uncut gem.
All glass items are manufactured at a glass furnace or magma glass furnace by a glassmaker. There are three sub-types of glass: Green, Clear and Crystal, each with different colour and value, but all with the same uses.
Green glass can be churned out in massive amounts if produced at a magma furnace, because there are no ingredients other than sand used and sand sources cannot be depleted. This makes it a valuable resource for construction; it is as valuable as dark and light stone (excluding obsidian), but can create a wider variety of final products, and some unique ones, such as gems and aquariums.
 Making glass items
In order to produce glass, sand must first be gathered in bags using the Collect Sand task at any glass furnace. Sand will be gathered from the side of the cave river or the outdoor river (if your biome has one). Collecting sand requires the "item hauling" labor, whilst moving sand bags to stockpiles requires furniture hauling. You will need spare bags in order to collect sand. Note that although Collect Sand does not utilize the furnace itself, or the skills of a glassmaking dwarf, it will block any subsequent tasks at that furnace until it is finished. Therefore, when entering mass production, it is more efficient to have extra glass furnaces strictly set to Collect Sand while the main furnaces run true glassmaking jobs - since collecting sand is generally slower than producing a glass item, a ratio of at least 3:1 is recommended. The "Collect Sand" task consumes no fuel.
See also Glass industry.
Glass can be manufactured into a wide variety of products:
- Raw glass is handled by the game like a rough (uncut) gem; thus, raw green glass makes an excellent training material for practicing the Gem cutter skill.
- Raw glass is also a frequent request of dwarves undergoing a strange mood.
- Glass can be formed into blocks which can then be used for most building purposes.
- Glass can be used to manufacture a number of furniture items, including armor stands, boxes, floodgates, portals, statues, tables, thrones and weapon racks.
- Glass windows can be made at a glass furnace as an alternative to making windows from gems.
- Cages may be made from glass. A glass cage is called a terrarium, and is unique among cages in that it may be converted into an aquarium. Terraria may not be used for justice applications.
- Glass vials are used in some types of plant processing, making extracts, and three clear glass vials are required to build an alchemist's laboratory. This makes the glass industry essential before a soap industry can be established.
- Glass can be formed into various toys and instruments; though you cannot directly produce glass crafts, they will occasionally be produced when cutting raw glass at a jeweler's workshop.
Glass items often have unique names:
- A glass chest is called a box.
- A glass door is called a portal.
- A glass cage is called a terrarium.
- A glass flask is called a vial.
 Material value
- Green glass has a value of 2.
- Clear glass has a value of 5.
- Crystal glass has a value of 10.