Raw Diamond: A Guide to Nature's Untouched Gem

Every polished diamond begins as a raw diamond: a crystal formed deep within the earth over billions of years and carried toward the surface by ancient volcanic eruptions. Long before it's cut, faceted, and set in a ring, it looks nothing like the sparkling stone most people picture.

This guide explains what a raw diamond is, what raw diamonds look like, how to recognize a raw diamond (and why you shouldn't rely on home tests), how an uncut diamond becomes a polished gem, and what all of it means if you're buying a natural diamond today.

WHAT IS A RAW DIAMOND?

A raw diamond, also called a rough or uncut diamond, is a diamond in its natural state, exactly as it was recovered from the earth. It hasn't been cut or polished.

Natural diamonds form roughly 90 to 120 miles below the surface, where intense heat and pressure crystallize carbon. Most of those that reach the surface arrived through deep-source volcanic eruptions, which created rock formations called kimberlite pipes. Others were eroded out of those pipes over time and carried by rivers into gravel deposits, called alluvial deposits.

WHAT DO RAW DIAMONDS LOOK LIKE?

Raw diamonds rarely sparkle. Most people who see one for the first time are surprised by how ordinary it can appear. Common characteristics include:

• Crystal shapes. The classic form is the octahedron, which looks like two pyramids joined at the base. Raw diamonds also occur as rounded dodecahedrons, cubes, and flat triangular twinned crystals called macles.
• A greasy or waxy luster. Instead of brilliant sparkle, the surface often has an oily, frosted, or slightly matte sheen.
• Surface markings. Many raw diamonds show small triangular etch pits called trigons, along with growth lines and pitted textures.
• A range of colors. Rough diamonds can be colorless, but many are yellowish, brownish, gray, or occasionally rarer colors such as pink or blue.
• Rounded edges. Diamonds that traveled through rivers can be worn smooth, looking almost like pebbles.

For more visuals, see what an uncut diamond looks like.

HOW TO RECOGNIZE A RAW DIAMOND

Recognizing a raw diamond with certainty requires gemological testing. Still, a few clues help experts separate likely diamonds from common look-alikes such as quartz, glass, and topaz:

• Crystal form: Octahedral or rounded crystal shapes are a strong indicator. Quartz typically grows as six-sided prisms with pointed ends.
• Luster: Diamond has a distinctive greasy-to-adamantine luster, even when rough.
• Weight for size: Diamond's density (specific gravity about 3.52) means it feels heavier than quartz of similar size.
• Thermal conductivity: Professional diamond testers can screen a clean rough surface, though results can be unreliable on rough or coated stones.
• Surface features: Trigons and characteristic growth patterns appear only on diamond crystals.

A word of caution: popular home "tests" like scratching glass or breathing on the stone aren't reliable. Many minerals can scratch glass, and while diamond is extremely hard, it can still chip or cleave along its crystal planes if struck. If you think you've found or inherited a raw diamond, have it examined by a qualified gemologist or gemological laboratory.

WHERE RAW DIAMONDS COME FROM

Major natural diamond producers include Botswana, Russia, Canada, South Africa, Angola, Namibia, and the Democratic Republic of the Congo. In the United States, Crater of Diamonds State Park in Arkansas famously allows visitors to search for diamonds and keep what they find.

Only a portion of mined diamonds are gem quality. Many rough diamonds have too many inclusions or too much color for jewelry and are used in industrial applications instead. That's part of what makes a fine, gem-quality natural diamond rare. Our post on ethical, conflict-free sourcing explains how responsible supply chains work.

FROM UNCUT DIAMOND TO POLISHED GEM

Turning a raw diamond into a polished stone is a precise, multi-step process:

1. Planning: The rough is scanned and mapped to find the cut that yields the best combination of size and beauty while avoiding inclusions.
2. Cleaving or sawing: The crystal is divided along planned lines, often by laser today.
3. Bruting: The diamond is shaped into its basic outline, such as round or oval.
4. Faceting and polishing: Facets are cut and polished at exact angles to create brilliance and fire.
5. Inspection and grading: The finished stone is examined and, for important diamonds, sent to a lab such as GIA for a grading report.

Cutting removes a significant portion of the rough. Round brilliants often retain well under half of the original crystal weight, which is one reason polished natural diamonds, especially rounds, command the prices they do.

RAW DIAMOND JEWELRY VS POLISHED DIAMONDS

Some people love the organic, earthy look of raw or minimally cut diamonds in jewelry. They're unique and full of character, but they don't sparkle the way a polished diamond does, and they're graded and valued differently.

For an engagement ring meant to be worn every day and treasured for generations, most buyers choose a polished, GIA-certified natural diamond. The certificate documents its quality, and the cut reveals the brilliance hidden inside the rough crystal. For more on the distinction, see raw diamonds: what it means for buyers.

FREQUENTLY ASKED QUESTIONS

Are raw diamonds worth anything?

Yes, but value depends heavily on size, color, clarity, and how much polished diamond can be cut from the rough. Many rough diamonds are industrial grade and worth relatively little.

Do raw diamonds shine?

Not much. Their greasy or frosted surfaces don't reflect light like polished facets. The brilliance appears only after cutting.

Can a diamond tester identify a raw diamond?

Sometimes, but rough surfaces and coatings can affect results. A gemological lab is the only reliable confirmation.

What does an uncut diamond look like most often?

Typically an octahedral or rounded crystal with a waxy luster and a pale yellowish, brownish, or colorless tone.

SEE WHAT A NATURAL DIAMOND BECOMES

A raw diamond is the beginning of the story. A beautifully cut, GIA-certified natural diamond is where that story becomes part of yours.

Mavilo offers natural diamonds at wholesale-direct pricing, and our specialists love explaining how each stone's journey from rough to polished shapes its beauty and value. Book a Diamond Appointment to see natural diamonds up close.