Mnemonic Device:

• True Geologists Climb Faults And Observe Quarries To Contemplate Deformation

Variation:

• Tall Gene Calls Florence At Our Quarters To Correct Dumbness
• Ten Gypsies Calculated F.A.O. Quartz as the Top Cor Diamond
• Texas Girls Can Fart And Other Queer Things Can Do
• Toronto Girls Can Flirt, And Other Queer Things Can Do

Additional Variation:

• The Greedy Child Found All Our feathery Quills To Copy Documents
• Tommy Gave Caroline Four Apples On fine Quick Tummy Clutching Dishes
  • includes “f” for feldspar in Orthoclase feldspar.

Explanation: to remember the order of Mohs’ hardness scale, from 1 to 10.

• Talc, Gypsum, Calcite, Fluorite, Apatite, Orthoclase feldspar, Quartz, Topaz, Corundum, Diamond