Skip to content
Free US shipping on orders $75+  ·  Every piece one of one  ·  Denver, Colorado

Not spiritual decor.

What Are, Crystals?

Ordered atomsRepeating pattern7 crystal systems

Crystals are solids whose atoms sit in a pattern that repeats in every direction, and most of the crystals people collect are minerals. This is the science side of geoslut: what crystals are made of, how they grow and how to tell them apart.

Read on.

Crystal science guides

Crystal science guides on hardness, how crystals and geodes form, and the kinds of quartz.

Mohs Hardness ScaleThe 10 index minerals from talc to diamond, plus every crystal we sell ranked by hardness.Talc 1How Are Geodes Formed?How a hollow in rock fills with quartz, amethyst or calcite, and how long it takes.Hollow noduleHow Do Crystals Form?How atoms lock into crystals from melts, hot water and vapor, and why some take millions of years.From meltsTypes of QuartzEvery major type of quartz, from amethyst to agate, and what makes each one look different.Mohs 7Chevron AmethystBanded chevron amethyst, plus amethyst from Uruguay, Brazil, Vera Cruz, Thunder Bay and Zambia.Mohs 7Elestial QuartzSkeletal quartz with stepped, many-tipped faces, usually smoky, and what the name elestial means.Mohs 7

What are crystals

Crystals are solids built from one small arrangement of atoms, called a unit cell, repeated over and over in every direction. That inner order shows on the outside as flat faces and sharp angles, which is why a quartz point looks cut even though nobody touched it. Table salt, snowflakes and sugar are crystals too. Glass is not: its atoms are frozen in a jumble. That rules out obsidian, which is volcanic glass, and amber and opal have no repeating atomic pattern either, even though shops sell all three next to quartz. Mineralogists sort crystals into seven crystal systems by the symmetry of that repeating unit.

What are crystals made of

Crystals are made of chemical elements locked together in fixed ratios, and the recipe is usually short. Oxygen and silicon are the two most common elements in Earth's crust, so quartz, which is silicon dioxide, turns up almost everywhere. Color usually comes from a trace of something extra: iron plus natural radiation makes quartz purple, aluminum plus radiation makes it smoky, and microscopic pink fibers make rose quartz.

Crystals, minerals and rocks

Crystals, minerals and rocks are three different things: a crystal is a structure, a mineral is a natural substance, and a rock is a mix. A mineral forms naturally, has a set chemistry and an ordered crystal structure, so quartz and fluorite count. A rock is a crowd of minerals stuck together, the way granite is mostly quartz, feldspar and mica. A crystal grown in a lab is still a crystal, but it is not a mineral. The USGS explains the difference between a rock and a mineral in more detail.

Rock science at geoslut

Rock science at geoslut starts from one rule: rocks are not spiritual decor. They are what 4.5 billion years of pressure, time and quiet violence leave behind, and the facts beat the folklore. Where we mention lore, we label it. Start with how crystals form, see why some rocks are hollow in how geodes form, rank everything we sell on the Mohs hardness scale, or sort the purple from the smoky in types of quartz. Every geoslut label names the mineral and its locality, so the science behind any piece is easy to look up.

What Are Crystals FAQ

Are crystals minerals?

Most crystals people collect are minerals, but not every crystal is one. Lab-grown bismuth and rock candy are crystals without being minerals, while amber and obsidian are sold as crystals but are not crystalline at all.

What is crystallization?

Crystallization is the process of atoms or molecules settling into a repeating pattern as a melt cools, a solution evaporates or a vapor condenses.

Are crystals worth any money?

Any crystal can be worth money, and what sets the price is rarity, size, color, damage and locality more than the name of the mineral.

Sources