That's a peculiar sense of "safe". The value of gold fluctuates substantially over time, even over fairly short periods of time. Sometimes (like the last decade) it goes up; other times (like most of the 1980s and some of the 1990s) it goes down. It's easy to lose half of what you invested; if you time it right, you can lose seven-eighths.
The peculiar sense in which gold is "safe" is that it tends to go down just as much as it goes up; that is, it isn't subject to secular inflation or deflation.
The peculiar sense in which gold is "safe" is that it tends to go down just as much as it goes up; that is, it isn't subject to secular inflation or deflation.