the technology that seems to defy gravity

Droffilc the master cartographer when he ventured out into the Magnificent Canyon he found a ancient city and in that city he found a strange technology. he and his crew inspected this technology and it made large slabs of rock just float there standing still. when they deactivated the device be detaching it it would make the slab fall. they took one of these things and brought it back and gave it to the council of elves. they then handed of to there artificers to study. this machine is a small simple box made of a strange metal and inside the box is a small magenta gem that pulses with magical energy. they have done many experiments with it and found it only seems to work on one type of rock witch is granite. they were able to after many years they were able to reverse engineer the device and make a spell that will lock objects in place momentarily for some time but not indefinitely. now using this spell they are trying to make a new device that will make it lock objects permanently in place but all that research has failed   they are looking for more gems or metals that match the ones in the device but nothing has turned up they theorize that they made or found these strange crystals that in combination continually cast the spell making it so it keeps objects in place. they have tried to recreate the crystal by trying to condense magic and enchant a gem to make a spell continuously take effect but that has mostly just ended in large explosions. the once that haven't failed repeat a spell once or maybe twice so they think there on the right track. there are only few of the crystals that repeat magical effects because those that failed exploded. they have tried it with varying types of gems and some have a high success rate than others so they think they have to find the right gem.