Crystals are the dominant technology in the Land of the Lost, most notably in the Pylons controlling the weather and property of the area. Often found embedded in the walls of caverns and some pillars in the area, they appear in a variety of colorful brightly glowing stones about the size of a large walnut and capable of glowing non-stop with an internal light while give off both heat and light as a by-product of their nature. They appear in the colors of red, yellow, orange, green, blue and white, each one with its own properties and attributes.
Harmless on their own, the crystals cause various reactions when brought in contact with each other. For example:
- Red and Green - creates a short-lived but blindingly bright light useful for driving away the Sleestak.
- Red and Yellow - creates an explosion useful in driving off Grumpy
- Green and Green - also creates an explosion
- Blue and Green - creates a force field useful in holding the Sleestak at bay
- Red, Blue and Yellow - creates an enormous nearly fatal shock that almost killed Rick Marshall
Furthermore, Jefferson Davis Collie III speculated that the blue crystals might be radioactive, or at least chemically toxic. Enik later explained that they were once called "fourth-dimensional nodes," and they were once grown artificially or otherwise constructed by the Altrusians for use as a power source for their technologies. Rick Marshall theorized that they might even power the dimensional doorways, later commiserating on the number of possible combinations of crystals. In fact, there are six possible combinations of four colors taken two at a time, and four possible combinations of four colors taken three at a time. The crystal matrix tables provide a 9x9 array, which would be capable of storing 162 bits (an astronomical number of possible states) if filled with crystals of four distinct colors.
- Jefferson Collie mentioned that blue crystals "make you sick" and discarded them when he mined them in his cave.
- In the Bible for Land of the Lost, blue crystals are said to have recording properties and can both record and play back "memories"