Hi! I'm Sophie. I'm 8 and in third grade. I have been collecting rocks since I was 5 which is 3 years. My collection is in a shoebox with dividers Dad made out of cardboard, and each rock has a number on a piece of masking tape and the numbers go with my list. The shoebox is a MUSEUM. It has a sign on it that says SOPHIE'S ROCK MUSEUM, ADMISSION FREE (or 1 rock). My little brother has to knock before he looks in it.

Dad has a book about rocks and minerals with pictures and we look up every rock in it. Some rocks we are not sure about. I put a question mark on those ones. A scientist doesn't just guess, Dad says. Dad is not a scientist, he sells insurance, but he read the whole book.

My favorite rock is the geode (number 12). My second favorite is the meteorite, which Dad says is PROBABLY not a meteorite, but read down at the bottom and decide for yourself.

OK so. In August we were walking along the railroad tracks by the old factory (with Dad, you're not allowed to go by the tracks alone) and I found a black lumpy rock about as big as an egg and it was HEAVY and it had a shiny melted-looking crust and little bumps and bubbles. And I said IT'S A METEORITE. Because meteorites come from space and they get melted on the outside when they fall through the air.

Dad looked it up in the book. Here is what the book says about real meteorites:

• They are usually really heavy for their size. Mine is heavy!
• A lot of them have iron in them so a magnet sticks to them. A magnet sticks to mine!!! (a little)
• They have a thin dark crust from melting called a fusion crust. Mine is dark and shiny!
• BUT they usually do NOT have bubbles or holes in them, because the inside didn't melt. Mine has bubbles. Hmm.
• And the book says the thing people find by railroad tracks and old factories that they THINK is a meteorite is almost always slag. Slag is the leftover junk from melting iron in a furnace. It is black and lumpy and bubbly and heavy and sometimes a magnet sticks to it because there's some iron left in it. And there's an old factory right there. Hmm hmm.

So Dad says it is "probably slag." He says PROBABLY. He didn't say definitely. A scientist doesn't just guess. So it's in the museum in its own special section with a label that says METEORITE (PROBABLY SLAG) (BUT MAYBE NOT). If you know how to tell for sure, e-mail me. Dad says there are people at universities who can test it and maybe we can write to one.

Even if it's slag I'm keeping it. It's the heaviest rock I have and I found it myself.

This is the coolest thing I learned. There is a scale of hardness from 1 to 10 called the Mohs scale (a man named Mohs made it up). 1 is the softest (talc, which is like baby powder) and 10 is the hardest (DIAMOND). A harder thing can scratch a softer thing but not the other way around. So you can figure out how hard your rock is with stuff from around the house! Here's the stuff and how hard it is:

How you do it: Try to scratch your rock with your fingernail. If it scratches, your rock is softer than 2 and a half (super soft, like talc or gypsum). If not, try the penny. If the penny scratches it, it's between 2 and a half and 3 (like calcite, #23!). If the penny doesn't, try the nail. If the nail scratches it, it's between 3 and 5 and a half (like a lot of stuff). If the nail does NOT scratch it, it's harder than 5 and a half, and then try to scratch GLASS with your rock. If your rock scratches the glass, it's really hard, like quartz which is a 7. Quartz scratches glass. That's how I proved #24 was quartz!

Important: Make sure it's really a scratch and not just a mark. Rub it with your finger. If it wipes off, it was just a mark from the penny and not a scratch. Dad's book says this trips people up.

The whole Mohs scale is: 1 talc, 2 gypsum, 3 calcite, 4 fluorite, 5 apatite, 6 feldspar (orthoclase), 7 quartz, 8 topaz, 9 corundum, 10 diamond. I memorized it. Dad made up a sentence to remember it but it's a silly one so I'm not putting it here.

The museum is a boot box (bigger than a shoe box) with cardboard walls Dad cut so there are 30 little rooms. Each rock has its own room with its number on tape. The lid has the sign. There is a magnifying glass in the box, a penny, a nail, and a little bottle of vinegar with a screw top (in a plastic bag because it leaked once). And a notebook which is the same list as on this page but with my handwriting.

Rules of the museum:

1. Knock first.
2. Don't take rocks out of their rooms without the museum director (me).
3. You can touch all of them except the obsidian (#14, sharp) and the geode (#12, you can look but the crystals are little and they break).
4. Admission is free, or 1 rock. If you bring a rock it goes in the museum and you get your name in the notebook. So far: Grandma (a lot), Uncle Ray, Emma, and my brother (a piece of gum, NOT ACCEPTED).

I have 4 rooms left. Then Dad says we need a bigger box. I say we need a bigger HOUSE.