Why Source Pumice from Hess?

An industrial materials company can be very good at what they do—competitive pricing, logistical expertise, consistency on spec, innovative and efficient production methods—but without a quality product, the high ground simply can’t be held. And while we pride ourselves on all of the above, we also count ourselves fortunate that our pumice deposit is world-class. Much of our processed pumice is exported into countries and regions that often have domestic pumice sources nearby. They buy Hess pumice because they require a superior pumice product.

Worldwide, our pumice enjoys advantages in whiteness (GE brightness of 84), hardness (Mohs’ scale 6), density (specific gravity of 2.35 g/cc) and natural purity. Our deposit has a confirmed yield in the millions of tons. Three modern processing facilities and a state-of-the-art testing lab ensure we can consistently deliver to the ordered specification.

Experience Matters

Hess has been extracting and refining pumice since 1958. Pumice is amazingly versatile, and over the years, we have developed pumice grades and grade blends to fit many industrial processes and consumer product formulations in arenas as diverse as concrete, horticulture, health and beauty, filtration, paint and coatings, industrial abrasives. We also actively seek new frontiers and even build new markets for pumice—like performance-boosting pozzolan for cementitious products and applications. We are very good at what we do, and we’ll help you get the right pumice product and spec for your needs.

Hess Pumice provides pure, refined, precision-graded pumice in over 70 standard and specialized blends. We stock many standard pumice grades in our warehouse to fill small and sample-sized orders. Our pumice is also available in several Mine Grades, sold on a per-ton basis. We also ship five Microfine Grades.

See the Pumice Grades and Types site page for more information on our product offerings.

A comprehensive quality assurance system provides precision particle distribution and exceptional purity. Three state-of-the-art pumice processing facilities deliver a full suite of grades and the ability to produce large orders for shipment within a two-week turnaround window. Our blending plant allows us to bag market-ready, pumice-enhanced products. A dedicated fulfillment center ensures we can quickly meet most sample and small order requests. In short, we are committed to holding the high ground as the premier supplier of pumice products worldwide.

Logistics Expertise

Our logistics expertise is critical to our ability to supply a global market with pumice products. Provide your requirements (specs, packaging, quantities, other) and we can provide pricing information on FOB, EX Works or any other Incoterm anywhere in the world.

Many standard grades are maintained in stock for immediate shipment of small-quantity orders. A two (2) week lead time is required (prior to shipment) for large orders and custom blends.

See the Logistical Expertise site page for more information on shipping.

Stable, Superior Pumice Source

While other pumice suppliers have come and gone over the past decades, rising and falling with the fortunes of single industries and economic fluctuations, Hess has been continuously supplying pumice products for more than sixty years. This stability is a credit to the Hess family for consistently taking the long-term view of the industry—relentlessly pursuing new industries and uses for pumice and standing firm on the commitment to efficiently and sustainably mine, process, package, and ship pumice anywhere. ••• ]

Key Benefits of Hess’ Pumice

Anchored by a long list of quality and performance benefits, we go to great lengths to ensure customer satisfaction in both our product and the entire purchasing experience.

arrowSpecialized impurity extraction technologies, combined with the natural pureness of the deposit, allow for extremely high purity content (98% - 99.8%, depending on grade).

arrowLow unit weight (40 - 50lbs per cubic foot, depending on grade).

arrowConsistent MOHS-scale hardness of 6. ••• ]

Quality Assurance Testing

Hess Pumice is continuously testing our product to ensure superior quality. Among the most common tests that we perform in-house are:

arrowSieve Size Analysis (ASTM C-136).

arrowParticle Size Analysis by Laser Diffraction (ASTM B822-10).

arrowWhiteness (Datacolor “Check” method). ••• ]

Physical and Chemical Pumice Properties

Pumice is not just pumice—it varies greatly in its physical and chemical properties (and usefulness) from deposit to deposit. Tabled below are the properties for the pumice mined, processed and shipped by Hess.

Chemical Name: Amorphous Aluminum Silicate
Hardness (MOHS): 6
pH: 7.2
Radioactivity: None
Loss on Ignition (LOI): 5%
Softening Point: 900 Degrees C
Water Soluble Substances: 0.15%
Acid Soluble Substances: 2.9%
Reactivity: Inert (except in the presence of calcium hydroxide or hydrofluoric acid)
Appearance: White Powder
Whiteness GE Brightness of 84
Silicon Dioxide: 76.2%
Aluminum Oxide: 13.5%
Ferric Oxide: 1.1%
Ferrous Oxide: 0.1%
Sodium Oxide: 1.6%
Potassium Oxide: 1.8%
Calcium Oxide: 0.8%
Titanium Oxide: 0.2%
Magnesium Oxide: 0.05%
Water: <1.0%
Crystalline Si02: None Detected

Pumice Grades

We produce over 70 standard and specialized pumice grades and grade blends and stock sample and small-order quantities of the most widely used pumice grades. For large orders or special grades and grade blends, allow 2 weeks for production-to-shipment ready. If we do not have a product in our catalog that meets a particular need, we gladly work with customers to develop custom grade blends.

See the Pumice Grades and Types site page for more information on grade types and packaging.


pumice store logo

arrow If you’d like to sample a pumice grade (or several), we have a nice selection of stock pumice grades available to purchase in small quantities via our Pumice Products Store.

arrow If you’d like to run tests and trials using our pumice in your commercial product formulation or industrial process, please contact us at with your request. We look forward to answering your questions, helping you select the best grade for your process, or helping you explore the fit of pumice for your needs. PLEASE include your name, your company or organization, pertinent project details, ship-to address, and preferred contact information in the sample request email.


We know pumice. We’ll answer your questions, help determine the ideal grade for your needs, get you sample grades for testing, or help figure out the logistics of getting pumice to you.

R&D: (208) 766-4777 x111

Sales: (208) 766-4777


Driving Directions:
Offices, Shipping Docks, Mine

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