Before hunting for rocks, teach the basics. Rocks are solid materials made of minerals. There are three main types: igneous (formed from cooled lava or magma—like granite, basalt, obsidian, pumice), sedimentary (formed from layers of compressed sediment—like sandstone, limestone, shale), and metamorphic (rocks changed by heat and pressure—like marble, slate, gneiss). Show pictures of each type and discuss how to recognize them. Igneous rocks often have crystals, are hard, and may look glassy. Sedimentary rocks have visible layers, may contain fossils, and often crumble more easily. Metamorphic rocks have wavy or banded patterns, are hard, and smooth. Discuss rock properties you'll use to classify them: color, texture (rough, smooth, glassy), hardness (scratches easily or not), weight (heavy or light for its size), and special features (sparkly bits, holes, layers). This prep makes field collection purposeful instead of just grabbing random stones.

Head outside to collect rocks. Good places: nature trails, riverbanks, beaches, parks, your backyard, or vacant lots (with permission). Bring a bag or bucket for collecting. Encourage your child to look for variety: different colors, textures, sizes, and types. 'Find one that's smooth, one that's rough, one that's really heavy, one with sparkles, one with layers.' Aim to collect 10-20 rocks that are different from each other—diversity makes classification interesting. Discuss where rocks come from as you hunt: 'This river rounded these rocks by tumbling them for thousands of years' or 'These rocks were probably broken off that cliff by freezing and thawing.' Make it an adventure, not a chore: 'Let's find the coolest rock we can!' Respect the environment—don't disturb wildlife, don't take rocks from protected areas (like national parks), and leave plenty behind. Collect only what you need.

Back home, spread the rocks out on a table or towel. Examine each one closely. Use a magnifying glass to see details: crystals, layers, fossils, holes, or sparkles. For each rock, describe it: 'This one is gray with white speckles, smooth, and heavy. That one is reddish, rough, with tiny holes.' Test properties: Hardness—try scratching it with a fingernail (soft rock), a penny (medium), or a steel nail (hard). If it scratches, it's softer. Texture—run your finger over it. Rough like sandpaper? Smooth like glass? Grainy? Weight—does it feel heavy or light for its size? Special features—does it have layers (sedimentary)? Crystals (igneous)? Bands or swirls (metamorphic)? Fossils (usually sedimentary)? Write or draw observations in a notebook: 'Rock 1: gray, smooth, heavy, has crystals.' This detailed observation is core science practice. Take your time—each rock is a little mystery to solve.

Now use your observations to classify the rocks. Start broad: sort into igneous, sedimentary, and metamorphic piles based on properties. Igneous: crystals, glassy, no layers, hard. Sedimentary: layers, may be softer, might have fossils or sand-like texture. Metamorphic: bands, swirls, hard, shiny or smooth. Some rocks will be obvious, others uncertain—make your best guess. Then narrow down: within each pile, can you identify specific types? Use a rock identification guide (book, website, app like Rock Identifier). Match your rock's properties to pictures and descriptions. 'Our gray rock with big crystals is probably granite—a common igneous rock.' 'This layered one that crumbles is sandstone—a sedimentary rock.' Label each rock with a small sticker or marker: 'Granite,' 'Sandstone,' 'Unknown Metamorphic.' It's okay to have unknowns—geology is complex. The classification process—observing, hypothesizing, testing, identifying—is the real skill you're building.

Create a permanent home for your rock collection. Options: egg carton with each rock in a compartment (label the lid), a divided box or tray, or a display shelf. Write labels for each rock: name, where found, date, and any interesting notes ('found at Grandma's creek, very smooth'). Arrange your collection logically: by type (all igneous together), by color, by location found, or by size. Display it proudly—rock collections are cool! Discuss next steps: continue adding rocks from new places you visit, trade with friends who collect, or specialize (only collect quartz varieties, or volcanic rocks, or fossils). Visit museums to see professional rock collections and learn more. Celebrate that your child is now a rock collector and amateur geologist. Explain that rock collecting has been a beloved hobby for centuries and connects you to Earth's history—every rock has a story millions of years old.