Raw Milky Quartz: How to Identify It and What It's Worth

Raw milky quartz is ordinary quartz (silicon dioxide, SiO₂) that looks cloudy white because it is packed with microscopic bubbles of fluid and gas trapped while the crystal grew. It has a Mohs hardness of 7, a white streak and no cleavage, and it is one of the most common minerals at the Earth’s surface. As a gem it is worth little: the quartz overview lists it as less desirable than clear or coloured quartz. Its real value lies elsewhere. White quartz veins are a classic host for gold, and the purest quartz bodies feed a specialist industry where processed high-purity quartz sold for US$500 to US$12,000 per metric ton in 2025 (USGS Mineral Commodity Summaries 2026).

This page is written for people who hold or are looking at ground with white quartz on it: claim owners, prospectors, consultants and buyers of mineral land. It covers how to tell milky quartz from look-alikes in a few minutes, what a piece or a vein is actually worth, where the big quartz districts are, when a white vein deserves an assay, and what the stone is used for in industry. A calculator further down turns an assay result into contained gold and value at a price you enter.

What raw milky quartz is and why it looks white

Quartz is a framework of silicon and oxygen atoms. Pure quartz, often called rock crystal, is colourless and clear. Milky quartz has the same chemistry and the same crystal structure; the difference is physical, not chemical. The Arkansas Geological Survey explains that the white colour comes from microscopic bubbles in fluid-filled cavities that scatter light which would otherwise pass straight through. The International Gem Society adds that these tiny cavities are usually filled with carbon dioxide or water (IGS quartz guide).

So the answer to the common question “the appearance of milky quartz is caused by what?” is simple: countless fluid and gas inclusions, too small to see one by one, acting like the droplets in a cloud. The more inclusions, the whiter and more opaque the stone. Pieces with fewer inclusions are translucent and are sold as “cloudy quartz crystal” or “milky clear quartz”. A single crystal can be clear at the tip and milky at the base, because the inclusions were trapped during an early, fast stage of growth.

How milky quartz forms

Most milky quartz grows from hot, silica-rich water moving through cracks in rock. As the water cools or loses pressure, quartz comes out of solution and fills the crack, forming a vein. Fast growth traps more fluid, which is why massive vein quartz is so often white. The same white quartz also forms in the cores of granite pegmatites, the very coarse-grained rocks that are mined for feldspar, mica and lithium, and in metamorphic rocks where heat and pressure moved silica into veins and lenses. Our guide to pegmatite deposits covers that second setting in more detail.

What “raw” means when you buy or sell it

“Raw” simply means the stone has not been cut, tumbled or polished. Raw pieces show broken, glassy surfaces, sometimes with crystal faces, rusty iron staining or bits of the host rock still attached. The name has no special meaning beyond that. Some sellers attach spiritual “meanings” and “benefits” to milky quartz; there is no scientific evidence for those claims, and this page sticks to what can be measured: hardness, durability, chemical resistance and what the rock may tell you about the ground it came from.

Milky quartz properties: hardness, streak and cleavage

Because it is ordinary quartz, every physical test gives the standard quartz result. The values below come from Geology.com and the Webmineral quartz data sheet.

Two of these trip people up. The streak of milky quartz is white, but because quartz is harder than most streak plates it often scratches the plate instead of leaving powder. And “milky quartz cleavage” is a trick question: quartz has no useful cleavage, which is one of its best identifying features.

How to identify raw milky quartz in the field

Several white minerals look alike from a few metres away. These five checks take a pocket knife, a piece of glass, a hand lens and, if you have it, a dropper of dilute acid.

Infographic

Identify milky quartz in 5 checks

1. 1ScratchA steel knife will not scratch quartz.
2. 2FractureCurved, glassy breaks, no flat cleavage.
3. 3AcidNo reaction in dilute acid; calcite reacts.
4. 4ShapeSix-sided crystals with pointed ends.
5. 5SettingNote rust, sulphides and vein direction.

1. Scratch test. Try to scratch the stone with a steel knife. Quartz will not scratch; instead it will scratch the knife and a glass plate.
2. Look at broken surfaces. Quartz breaks with curved, glassy, shell-like surfaces. Flat, shiny, stepped surfaces point to a mineral with cleavage, such as calcite or feldspar.
3. Acid test. A drop of dilute hydrochloric acid makes calcite react; Geology.com’s calcite page lists calcite’s hardness as 3 and its cleavage as perfect in three directions. Quartz does nothing.
4. Check the shape. Six-sided crystals with pointed ends are quartz. White feldspar forms blocky crystals with two cleavage directions near right angles.
5. Read the setting. A white band cutting across layered rock is likely a quartz vein. Note rusty spots, cavities, metallic grains and the direction the vein runs: these matter far more to value than the quartz itself.

Feldspar and quartz often occur together in pegmatites, and both are mined as industrial minerals; see feldspar, quartz and mica and their roles for how the three are separated and sold.

Is milky quartz valuable? What sets the price

Usually not, by itself. Milky quartz is among the most abundant forms of quartz, and the IGS notes it is little used in gems except for cabochons (IGS). Most raw pieces sell cheaply as landscaping rock, aquarium or garden stone, tumbled stones and beginner specimens. So “is milky quartz rare?” has a clear answer: no. That does not mean every white rock is worthless. Value depends on which of four very different markets a piece belongs to.

Chart

US high-purity quartz value range

US$ per metric ton, low and high end of reported range

Only the last two can make a deposit worth real money, and neither can be judged by eye. The USGS defines high-purity quartz as natural quartz with less than 100 parts per million of total impurities, equal to 99.99% purity, and it reported a 2025 value range of US$500 to US$12,000 per metric ton (USGS MCS 2026, quartz). The wide range reflects how much processing and how pure a product is. The chart shows how the top of that range has moved.

Is milky quartz worth anything as a gem?

Only modestly. Polished milky quartz appears as beads, cabochons and carvings, usually at low prices. A piece is worth more when it carries something rarer: native gold, a well-known locality, unusual inclusions such as rutile needles, or crystals large and sharp enough for collectors.

Where milky quartz is found

Milky quartz occurs on every continent. The three most common settings are hydrothermal veins (quartz deposited from hot water in cracks), granite pegmatites, and metamorphic rocks. Some districts stand out for size or purity.

The Ouachita Mountains, Arkansas and Oklahoma

The best documented quartz district in the United States runs through the Ouachita Mountains. The Arkansas Geological Survey describes a belt about 30 to 40 miles wide that extends about 170 miles west-southwest from Little Rock into eastern Oklahoma, with veins formed during mountain building some 280 to 245 million years ago (Arkansas Geological Survey). Veins reach about 60 feet wide in Arkansas and nearly 100 feet in Oklahoma. Veins hosted in shale are typically massive milky quartz, while sandstone-hosted veins more often hold pockets of clear crystals. Arkansas made quartz crystal its official State Mineral in 1976. The town of Mount Ida, shown in the satellite image at the top of this page, sits in the heart of this belt.

Spruce Pine, North Carolina

Around Spruce Pine, two companies produced high-purity quartz in 2025 from pegmatite that was mined at the same time for feldspar and mica, according to the USGS silica statistics and MCS 2026. The rock is crushed, washed, scrubbed and sorted, then purified by physical, chemical and thermal steps. The USGS estimated the United States to be the leading producer of HPQ, with other sources in Australia, Brazil, Canada, China and Russia.

Brazil and Madagascar

Natural quartz crystal used as feed for growing cultured quartz is called lascas. The USGS reports that most lascas is mined in Brazil and Madagascar (USGS MCS 2026). Minas Gerais in Brazil and central Madagascar are also major sources of quartz specimens and carving rough.

Gold districts with white quartz veins

Many historic hard-rock gold districts are, at heart, fields of white quartz veins: the Mother Lode of California, the Carolina slate belt, Victoria in Australia, and the greenstone belts of Ontario, Quebec, Ghana and Tanzania. In these places the quartz itself is the ordinary part; the gold, sulphides and structure are what matter. Our overview of types of gold deposits explains how quartz-vein gold differs from other deposit styles, and types of ore deposits places it among all the major ore types.

▶ Tells the story of the 1880s Arkansas gold boom and what the state’s geologists found in its quartz veins. · 6:31

Milky quartz and gold: when a white vein is worth sampling

The IGS puts it plainly: vein quartz is often white and frequently contains gold (IGS). History agrees. Gold has been part of North Carolina’s history since 1799, when a boy found a 17-pound gold nugget, and the state became the nation’s first gold-producing state; mining later moved underground to work the lodes (North Carolina Geological Survey). The same circular notes that gold is usually seen as irregular plates, scales and masses rather than as crystals.

Most white quartz carries no gold worth mining. These features make a vein worth a sample:

• Rusty staining and cavities. Brown or orange iron oxide and empty boxwork holes often mark weathered pyrite or other sulphides, which can carry gold.
• Visible sulphides. Brassy pyrite, silvery galena or dark sphalerite in the quartz show that metal-bearing fluids passed through.
• Banding and breccia. Layered quartz or broken rock cemented by quartz records repeated pulses of fluid.
• Grey or smoky zones. Fine sulphides can turn quartz grey; very clean, glassy white quartz is often barren.
• Structure. Veins along faults or shear zones, and old workings or placer gold in streams below, raise the odds.

The USGS notes that a lode prospector’s first questions are the average gold content per ton of rock and the size of the deposit, because together they set the value (USGS, Gold). That needs a fire assay from an accredited laboratory, not a visual guess. Our guide to choosing a gold assayer explains how samples are taken and priced. Grade is reported in grams per tonne (g/t), the grams of gold in one metric ton of rock; 1 troy ounce is 31.1035 grams.

Once you have an assay, the calculator below turns it into contained gold and gross value. It does not account for mining, processing, royalties or tax, so treat the answer as an upper bound, not a profit.

Industrial uses of quartz and high-purity silica

Industry buys quartz for its chemistry and its toughness, not its colour. Massive milky quartz, quartzite and quartz sand all serve as silica sources once they are crushed and cleaned. The main uses are:

▶ Follows gold from rock to ring: found, drilled, crushed, dissolved, recovered and refined. · 5:27

Chart

US silicon metal price

Average, US cents per pound of silicon

• Glass. Silica is the main ingredient of most glass; glassmaking took about 7% of US industrial sand by tonnage in 2025 (USGS).
• Silicon metal and ferrosilicon. Quartz and quartzite are smelted with carbon to make silicon. In the United States, ferrosilicon was sourced primarily from domestic quartzite, and silicon metal went mainly to aluminium alloys and silicones (USGS MCS 2026, silicon).
• High-purity quartz. Fused quartz crucibles for growing the silicon ingots that become solar and semiconductor wafers, fibre-optic cable, high-temperature lamp tubing and specialty glass all rely on HPQ (USGS MCS 2026).
• Foundry, filtration and fillers. Silica sand lines metal-casting moulds, filters drinking water and fills paints and plastics.
• Abrasives and construction. Hard, angular quartz grains serve in sandpaper, blasting media and engineered stone, and quartz-rich rock is crushed as aggregate.

The USGS gives an average US silicon metal price of 130 US cents per pound of silicon in 2025, down from 361.86 cents in 2022, and estimates China’s 2025 silicon metal output at about 4 million tonnes, the largest of any country (USGS MCS 2026).

Silica sand: how much is used and for what

Most industrial silica comes from quartz-rich sand and sandstone rather than from vein quartz. In 2025 the United States sold or used an estimated 120 million tons of industrial sand and gravel worth about US$4.5 billion, from 207 operations in 38 states; Texas, Wisconsin, Oklahoma and Louisiana supplied 77% (USGS MCS 2026, industrial sand and gravel). About 81% went to oil and gas wells as fracturing sand and well-packing sand. The average value was about US$36 per metric ton, which shows why ordinary silica only pays when it sits close to the buyer.

Chart

US industrial sand and gravel sold or used

Million metric tons

Chart

What US industrial sand is used for

Share of tonnage sold or used, 2025

That price gap is the key commercial lesson for a quartz owner. Bulk silica earns tens of dollars per ton; processed high-purity quartz can earn hundreds or thousands. The difference lies in chemistry, processing and a reliable buyer, which is why HPQ supply comes from only a few places worldwide.

Safety when breaking or crushing quartz

Quartz is chemically harmless as a solid, but its dust is not. OSHA warns that cutting, grinding, drilling and crushing stone creates respirable crystalline silica particles, and that breathing them raises the risk of silicosis, lung cancer, chronic obstructive pulmonary disease and kidney disease (OSHA). Wet the rock before crushing samples, wear a fitted respirator rated for silica dust, and wear eye protection, because quartz breaks into razor-sharp shards.

Before you collect or sample, get the landowner’s or claim holder’s permission and check the rules on public land. Never use mercury to recover gold from crushed quartz; it is toxic and banned or restricted in many countries. Let a licensed laboratory or processor handle recovery.

How satellite imagery helps on quartz-vein ground

A satellite cannot see a single vein of milky quartz under soil, but it can map what often comes with gold-bearing quartz: iron oxide staining, clay alteration and long linear structures such as faults and shear zones. For a claim owner or a buyer, a satellite screen of a licence block helps decide where to walk, sample and trench first. Farmonaut’s satellite-based mineral detection reports turn that screen into ranked exploration targets; they sit ahead of sampling and drilling and are not a resource estimate. To ask for a report on your own ground, use the mining query form.

▶ Explains how satellites map iron staining, clay alteration and faults around gold-bearing ground. · 4:25

Frequently asked questions

What is milky quartz?

Milky quartz is ordinary quartz, silicon dioxide, that looks white and cloudy because it contains countless microscopic fluid and gas inclusions. It has the same hardness and chemistry as clear quartz. For more background and decorative uses, see our milky quartz facts and uses page.

What causes the appearance of milky quartz?

Tiny bubbles of water, carbon dioxide or both, trapped while the crystal grew, scatter light and make the stone look white. The Arkansas Geological Survey and the IGS both describe this cause.

What is the hardness of milky quartz?

Milky quartz has a Mohs hardness of 7. It scratches glass and steel, and only harder minerals such as topaz, corundum and diamond scratch it.

What is the streak of milky quartz?

White. Because quartz is about as hard as or harder than an unglazed porcelain streak plate, it often scratches the plate rather than leaving a visible line.

Does milky quartz have cleavage?

No useful cleavage. It breaks with a curved, shell-like conchoidal fracture, which helps tell it apart from calcite and feldspar.

Is milky quartz valuable?

Usually not as a gem or a specimen; raw pieces sell cheaply. Value comes from gold or other metals in a vein, from collector-quality crystals, or from very pure quartz that can be processed into high-purity quartz, which the USGS valued at US$500 to US$12,000 per metric ton in 2025.

Is milky quartz rare?

No. It is one of the most common forms of quartz and is found in veins, pegmatites and metamorphic rocks on every continent.

Where is milky quartz found?

In hydrothermal quartz veins, granite pegmatites and metamorphic rocks worldwide. Well-known areas include the Ouachita Mountains of Arkansas and Oklahoma, Spruce Pine in North Carolina, Minas Gerais in Brazil and Madagascar.

Does milky quartz contain gold?

Sometimes. Many gold deposits are white quartz veins, and the IGS notes that vein quartz frequently contains gold. Rusty staining, sulphides and banding are better signs than the quartz alone; only an assay confirms the grade.

What is the difference between milky quartz and clear quartz?

Only the inclusions. Both are silicon dioxide with hardness 7. Clear quartz, or rock crystal, has few inclusions and lets light through; milky quartz is full of them and looks white.

What is milky quartz used for?

Raw pieces are used as decorative and landscaping stone, tumbled stones and specimens. Crushed and purified quartz feeds glass, silicon metal, foundry sand, fillers and, at the highest purity, crucibles and electronics.