Minerals, Rocks, Gemstones, Crystals - What's the Difference?

Design Idea F55R Necklace and Earrings
by Dan Day, Exclusively for Fire Mountain Gems and Beads®

A Brief, Painless Introduction to Nature's Hard Stuff

Minerals, rocks, gemstones, crystals: unless you are a professional or amateur geologist--or maybe earned a merit badge studying them as a scout--you probably will have a hard time explaining the differences amongst these four hard substances found in nature. Because you are interested in jewelry and would like to be more of an expert, we can fix that right here, right now:

Mineral - This is where it all starts. The standard geological definition of minerals is they are naturally occurring inorganic elements with a definite chemical composition and ordered internal structure. Examples: calcite and quartz. Minerals form the basis for rocks, crystals and gemstones.

Rock - Because they both consist of multiple minerals, you can correctly refer to a rock as a stone. (see the “Rock versus Stone” box below). Rocks are commonly formed from a combination of six minerals: amphibole, feldspar, mica, olivine, pyroxene and quartz (some experts expand that number to six, others to eight). For example, granite is formed from quartz and feldspar.

Rock versus stone - although used somewhat interchangeably, the Oxford English Dictionary (OED), defines rock as "A large rugged mass of hard mineral material or stone." Examples: Plymouth Rock, Ayers Rock, The Rock of Gibraltar or a generic "large rock formation." The OED defines stone as "A piece of rock or hard mineral substance of a small or moderate size." The word "rocks" can be substituted for "stones."

Crystal - You've certainly heard plenty about them. But what exactly are crystals? According to Walter Schumann's Gemstones of the World, crystal is a uniform body with geometric crystal lattice. Snowflakes, diamonds and table salt are examples of large crystals. Varying lattice structures and their chemical components result in varying physical properties of the crystals and gemstones made of crystal. Crystals can be found in rocks since crystal is a mineral and rocks can be made of more than one mineral. The mineral-based crystal we are discussing here is not to be confused with crystal glass (lead crystal) products manufactured and sold by companies such as Crystal Passions and Preciosa.

Gemstone - This one has a rather imprecise definition. Basically, it's just about any mineral, crystal or semi-precious stone that has been cut and polished and used for jewelry. Because of that, there are more than two hundred gemstones in use.

Of course, we've just mined the surface of this topic. And maybe you've become interested enough to dig deeper. We suggest you check out our Gemstone Info and Gem Notes as well as Walter Schumann's revised and expanded edition of Gemstones of the World. From there you may go online to tap many rich veins of information or enroll in local college course. You may not end up being a geologist or gemologist, but now you have a solid grounding in the basic terminology.

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