This clock is made of beautiful, naturally occurring agate. This time keeper makes a nice decoration for a table top and brings some of nature’s beauty inside the home. Since agate is a naturally occurring rock, structures and crystal habits will vary from clock to clock. Some clocks may have more bands, and some may have more visible crystals than others. All agates are made of the mineral quartz. This is an agate that has been colored blue to enhance its natural features. Agate clock will measure 5″ x 5″ or larger.