Genuine Leather" isn’t as simple as just a piece of skin; it’s a pyramid.

"Genuine Leather" isn't as simple as just a piece of skin; it's a pyramid. The peak is "Full-Grain," the base is "Bonded Leather." In between, every layer has a confusing name, a tenfold price difference, and a hundredfold difference in lifespan. Before buying bags, shoes, or sofas, get a clear look at this "Pyramid Map" so you don't waste your money.

1. The Peak: Full-Grain
It retains the most complete natural texture and pores of the animal hide, with the tightest fibers.
Characteristics: Clear pores, a touch that is slightly grippy yet tough; it develops a glossy "patina" over time.
Uses: Hermès saddle leather, high-end work boots, Rolls-Royce seats.
Price: Starting at 5–15 USD per sq. ft.; top-tier vegetable-tanned leather can reach 40 USD.
The Bottom Line: If you want an heirloom, choose this. If you want "flawless," don't choose this—scars are its ID card.

2. The Upper Layer: Top-Grain
The natural surface is lightly sanded to remove scars, then pressed with an artificial texture and coated with polyurethane.
Characteristics: Silky touch, waterproof, stain-resistant, almost scar-free, but the natural pores are gone.
Uses: The base leather for classic LV coated canvas, official iPhone leather cases, mainstream luxury car seats.
Price: 3–8 USD per sq. ft.
The Bottom Line: If you want a hassle-free material that is "like leather but also like plastic," choose this. If you want something that gets more beautiful with age, look elsewhere.

3. The Middle Layer: Split Leather
The raw hide is sliced horizontally in two. The top part becomes Top-Grain, while the bottom becomes Split. The fibers are loose; the surface is sprayed with PU and pressed with a "faux grain." It is commonly known as "Bi-cast leather" or simply "Split."
Characteristics: The back is rough suede, the front is a plastic film. Bending it reveals dense "crackle" patterns.
Uses: Cheap briefcases, sneaker uppers, the side panels of sofas (non-contact areas).
Price: 1–3 USD per sq. ft.
The Bottom Line: "Genuine leather" bags under 500 RMB (approx. 70 USD) are 90% likely to be this. Lifespan is 1–2 years; don't expect a patina.

4. The Base: Bonded Leather
Leather scraps and fibers are glued together and pressed into sheets. If it contains at least 51% leather content, it can legally be called "Genuine Leather."
Characteristics: The cross-section looks like compressed wood board; you can scratch off debris with a fingernail; smells pungent.
Uses: Dirt-cheap "genuine leather" sofas, hotel headboards, office chair armrests.
Price: 0.3–0.8 USD per sq. ft.
The Bottom Line: If you see "Genuine Leather" sold at cabbage prices, it's likely this. Over time, the surface will peel and crack like a map—impossible to repair.

5. The Branches: Suede & Nubuck
Turning the Split side outward creates Suede; lightly sanding Top-Grain to create a short nap makes Nubuck.
Characteristics: Feels like peach skin, but gets ruined immediately if it touches water.
Uses: Clarks Desert Boots, designer brand small crossbody bags.
Care: Waterproof spray + eraser + brass brush. Do not wear to a hot pot dinner on a rainy day.

6. Special Process: Vegetable Tanning vs. Chrome Tanning
Vegetable Tanning: Uses plant tannins. Eco-friendly, moldable, turns browner with use. Downside: Fears water, deforms easily.
Chrome Tanning: Uses trivalent chromium. Soft, water-resistant, can be dyed any trendy color. Downside: No "patina" story.
Market Reality: 90% of leather goods are Chrome Tanned, 9% are mixed tanned, and only 1% is top-tier Vegetable Tanned—Hermès level.

7. One-Minute Self-Test Method
1. Check the Cross-section: Full-Grain has dense fibers and no glue marks; Split leather reveals a "plastic film + spongey layer."
2. Press for Wrinkles: On Full-Grain, fine wrinkles disappear naturally after pressing; on Bonded leather, a press creates a permanent dead crease.
3. Smell: Full-Grain has a faint animal fat scent; Bonded leather smells of chemical glue and paint.
4. Burn a Thread: Pull a stitch and burn it. If it contains plastic, it will melt and drip; pure leather burns to ash and smells like burning hair.

Remember:
"Genuine Leather" is just a legal baseline, not a guarantee of quality;
"Full-Grain" is the starting point for collector-grade items;
Price is not about thickness; it's about "how much of the original skin remains."

Next time a salesperson says, "This is top-layer genuine leather," ask them first: "Is it Full-Grain or Corrected-Grain (Top-Grain)?"—That one sentence will let them know: You know your stuff.