Rocks do not grow like organisms—they do not feed or increase in size from within, but crystals really do grow: they add successive layers of atoms from a solution, usually over thousands or even millions of years. By contrast, the stones that “grow” in fields every year have not grown at all—they are pushed toward the surface by frost.
This question is only seemingly childish. The answer depends on what we are talking about: a rock, a crystal, or a boulder that emerges from the ground in the middle of a field every spring. Each of these “stones” behaves differently—and each has its own story.
Crystals really do grow—layer by layer
A crystal does not eat or breathe, yet it grows. When dissolved silica circulates in a hot underground solution, its particles settle on a nucleus and arrange themselves into a perfectly ordered lattice—atom by atom, layer by layer. This is how crystallization works: a crystal continues to grow as long as it has material to build with and room to expand.
The most beautiful proof comes from crystal clusters and geodes. These are cavities in rock where quartz or amethyst crystals accumulated from circulating hydrothermal solutions over thousands—and sometimes millions—of years. That is why a split-open geode is lined inside with a sparkling brush of crystal points—each one literally grew inside a stone chamber.
How do stones form?
Rock has a different biography. It is born when magma solidifies into granite or basalt, when sand and silt compact on the seafloor into sandstone and limestone, or when older rocks are transformed deep within the Earth under immense pressure and heat. From that moment on, the stone no longer grows—water, ice, and wind can only break it down and round it off, so over time it generally becomes smaller.
Amber followed a separate path: it is tree resin that hardened and lay buried in sediments for millions of years. We explain in detail how amber forms in a separate article.
Where do the new stones in fields come from every year?
Farmers could swear that stones grow in fields: every spring they gather a fresh “harvest” from ground that looked clear in autumn. The culprit is frost heaving. The soil repeatedly freezes and thaws, and these small seasonal movements push boulders toward the surface year after year—the stone has not grown by a single millimeter; it has simply ridden upward like an elevator.
The boulders themselves did not come from nowhere either. Most fieldstones in Poland are erratics that glaciers dragged from Scandinavia and left behind when they melted thousands of years ago. The field does not “give birth” to them—it merely gives them back.
How much does a stone grow?
In nature, crystallization is usually measured in thousands and millions of years. Even cave stalactites, considered relatively fast-growing, typically increase by anywhere from fractions of a millimeter to a few millimeters per year, depending on the amount of water and dissolved carbonate. Travertine and cave pearls accumulate “before your eyes”—that is, over entire centuries, as far as geology is concerned.
By contrast, salt or alum can crystallize in a jar at home within a few days or weeks. The mechanism is the same; the speed is incomparable. It is the simplest way to see with your own eyes how a stone grows.
From the Brazi studio
The crystal clusters and druses in our studio are literally stones that grew—nature arranged them over thousands of years, and we only added the setting. In our collection, you will find both raw crystal clusters and jewelry featuring this mineral—10% off with the code BRAZIBLOG10.
So when someone asks whether stones grow, the answer is: rocks do not, but crystals do—just at a pace that makes a human lifetime seem like a blink. And if you would like to get to know the most famous of these “grown” minerals better, explore our guide to rock crystal.
Since crystals grow inside cavities in rock, it is no wonder that for years people thought they were the work of something more than nature—our separate article explores the most famous such misconception: crystal skulls.