Granite, marble, quartz or porcelain: what is the difference, and what belongs outdoors
One line each: granite is cooled magma, hard, weather-resistant, low absorption, use it outdoors. Marble is beautiful but acid-sensitive and frost-prone, use it indoors. Quartz and porcelain are man-made with controllable patterns but without the outdoor durability of natural granite.
What is the fundamental difference between granite and marble?
How they formed. Granite is crystallised magma: granular, hard, low water absorption. Marble is metamorphosed limestone: veined, softer, acid-sensitive. Under sun, rain and freeze-thaw cycles, granite holds up far better.
Why should marble stay out of exterior work?
Acid rain and frost. Acid attacks the surface, and water that penetrates and freezes lifts and cracks the face. In humid southern climates or northern freeze-thaw regions, exterior marble is a high-risk choice. Interior walls, floors and worktops are where it belongs.
What are quartz and porcelain exactly?
Both man-made. Quartz is crushed quartz bound with resin, common for kitchen worktops. Porcelain slab is a ceramic process producing large-format thin panels that can imitate any stone. Both offer stable, near-identical colour, but neither has the outdoor durability of natural granite, and neither suits large load-bearing paving.
How do you tell them apart when buying?
The code is the most reliable signal: in the Chinese standard, G designates granite and M designates marble. Then look at a broken edge: granite fractures into grains, marble shows directional veining. Granite also feels heavier in the hand.
So what should go on exterior paving?
Granite. Plazas, kerbs, steps and ventilated facades are all granite territory. If another material must go outside, ask about water absorption and freeze-thaw performance first. A sample looks good under showroom lighting; rain is the real test.