Diamonds are hard minerals, in a scale of hardness  is 10.

Talc is really soft, hardness 1.

Salt you use for food sometimes.and salt look like crystals if magnified

THESE PIECES OF SALT ARE L I T T L E THEY CAN NOT BE PIECES OF RUBY AND MOHS SCALE OF MINERAL HARDNESS

TALC HARD 1

GYPSUM 2 CALCITE 3

FLUORITE 4

APATITE 5

FELDSPAR 6 QUARTZ 7

BERYL 8 CORUNDUM 9

DIAMOND 10 NORMAL FINGER NAIL CAN SCRATCH 1 TO 2 STONE NAIL 1 TO 5

SCIENTISTS WHO STUDY ROCKS IS A  GEOLOGIST

GEOLOGISTS HAVE DISCOVERED AND NAMED MORE THAT 5000 MINERALS

VERY TINY ROCKS IS SAND

SOMETIMES PEBBLES CAN BE GRAY AND OTHER COLORS! SOME OF US CALL IT GRAVEL.

THE NAME FOR THE BIGGEST ROCK IS A BOULDER

ROCKS ARE MADE OF ONE OR MORE MINERALS. A MINERAL IS SOLID PURE SUBSTANCE THAT OCCURS NATURALLY.