What is the hardest natural mineral on Earth?

Which popular gemstone is actually a form of corundum?

What rock type is formed from cooled lava?

Which mineral is commonly known as 'fool's gold'?

What color is pure quartz?

Which rock type forms from layers of sediment over time?

What is the main mineral component of table salt?

Which gemstone is traditionally associated with April birthdays?

What rock is formed when limestone is subjected to heat and pressure?

Which mineral leaves a red-brown streak when scratched?

What is the softest mineral on the Mohs scale?

Which popular gemstone is made of fossilized tree resin?

What color is malachite typically?

Which rock type often contains visible fossils?

What is the primary mineral in pencil 'lead'?

Which gemstone is made by oysters?

What rock is often called 'black gold'?

Which mineral is used to make plaster of Paris?

What color is most commonly associated with sapphires?

Which rock type is created by heat and pressure changing existing rocks?