Generally speaking, yes. They do get hot, though, so they’re best kept away from children. However, they’re just like any other lamp – unlikely to burn furniture or set anything on fire, so long as you’re careful. Lava lamps are also fragile. The bottles are made from glass, so although they’re pretty tough, they can break. And if you shake a lava lamp hard enough it will stop working properly and become cloudy. So don’t do that. How long can I leave a lava lamp on for? While the liquid in the bottle is clear, the lava is red. Once switched on, it takes about three to four hours to get the lava flowing nicely. But when it does it casts a lovely red glow. Even better, once that lava is moving about, it creates beautifully iconic 60s lava shapes. Not to sound trite, but you must always read the instructions on your individual lamp. Generally, manufacturers recommend leaving them on for a maximum of eight hours. After that, they should be allowed to completely cool and resettle. Aside from anything else, this will undoubtedly prolong the life of your lamp.