1.   Bacterial magnetite crystals also have this property, as it improves the strength of the magnet.

2.   He created very similar magnetite crystals in the lab, simply by heating up a carbonate mineral called siderite.

3.   My humanoid characters possess magnetite crystals, especially around the membrane that covers and protects the brain.

4.   On the contrary, she said, she found teardrop-shaped magnetite crystals that are thought to occur only in living microbes.