Mineral Properties

Rockling — Mineral Properties Geode Garden

Hey, explorer! Rockling here. Welcome to Geode Garden.

I check these specimen shelves on my morning walks.

Hmm... the Grumblies have mixed up the labels again.

Will you help? We'll compare clues, one at a time.

Here's what I know. Minerals have properties we can compare.

Color is the color we see on the outside.

But one mineral can come in several colors.

Quartz can be clear, purple, pink, or smoky.

Different minerals can also share the same color.

So a purple sample needs more than a purple label!

Luster describes how light reflects from a mineral's surface.

It might look metallic, glassy, or dull.

Our lantern helps us observe. It doesn't decide mineral identity.

Hardness means resistance to scratching.

It doesn't mean how heavy a sample is.

And a hard mineral can still break when struck.

A harder material can scratch a softer one.

Suppose sample A scratches sample B.

That scratch is evidence that A is harder.

Use prepared test records here. Ask an adult before testing specimens.

Streak is the color of a mineral's powder.

It can differ from the color of the outside.

Hematite can look dark gray, but leave reddish-brown powder.

That reddish-brown streak is an important identification clue.

Scientists compare several properties with reliable reference information.

A single shiny surface usually isn't enough to identify something.

I like mysteries that give us more than one clue.

Help me read this record. Which observation describes hardness?

A glassy shine, or resistance to scratching? Take your time.

Resistance to scratching! The glassy shine describes luster.

You matched the observation to the right property. Nicely done!

A gray sample leaves reddish-brown powder. What's its streak?

Reddish-brown. For streak, we describe the powder, not the surface.

Let's collect our clues. Color describes appearance; luster describes reflection.

Hardness describes scratching resistance. Streak describes powder color.

Compare several properties before choosing an identification.

Now our garden records make much more sense.

The Grumbly's confusing labels still need your careful thinking.

You don't have to rush. Look closely, and use your evidence.

Train more, start this adventure, or choose another map destination.

Free Mineral Properties teacher guide and practice (PDF)