Amorphous (non-crystalline) in structure and composed primarily of aluminum silicate, pumice is a naturally calcined volcanic glass foam consisting of highly vesicular strands permeated with tiny air bubbles. It is these frothy, friable glass vesicles that, when carefully refined to various grades, give pumice its unique and infinitely useful qualities.
The exceptional Hess pumice deposit originated with an ancient volcano that spewed volcanic ash onto the surface of vast inland paleolake known as Lake Bonneville (which once covered much of present-day Utah and extended into Idaho and Nevada). The pumice was washed over centuries of relentless wave action, freeing the heavy impurities to fall to the bottom and piling the purified pumice in a deep deposit against the northern shore.
Pumice is extremely versatile and widely applicable, used in an impressive assortment of industrial processes and consumer products. Uses include: lightweight aggregate for insulating construction concretes and precast concrete products, performance-boosting concrete pozzolan, lightweight stucco and bonding mortar product aggregate, an aggressive-yet gentle industrial abrasive and polishing media, exfoliating and scrubbing grit, engineered horticultural soil component, soilless grow media, native soil amendment, composting supplement, pet and livestock care, functional filler and extender in paints and epoxies, and as a water and beverage filtration media.
The information below is included on each grade-specific technical data sheet (TDS). Download: General TDS sheet (sans particle size data).
|PHYSICAL PROPERTIES OF HESS PUMICE|
|Description: Non-crystalline (amorphous) foamed glass stone of volcanic origin. Grey-white (stone grades) to white (powder grades) in appearance.|
|Brightness: (GE) 84|
|Hardness: (MOHS) 6|
|Reactivity: Inert (except in the presence of calcium hydroxide or hydrofluoric acid)|
|pH: 7.2 (neutral)|
|Loose Bulk Density: Varies with grade (available on the Technical Data Sheet for each grade)|
|Specific Gravity: 2.35|
|Softening Point: 900 Degrees C|
|Water Soluble Substances: 0.15%|
|CHEMICAL PROPERTIES OF HESS PUMICE|
|Chemical Name: Amorphous Aluminum Silicate|
|Composition: Primarily made up of Silicon Dioxide and Aluminum Oxide with traces of other oxides (as follows).|
|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%|
|Crystalline SiO2: none detected|
|AGGREGATE PROPERTIES OF HESS PUMICE|
|PROPERTY||ASTM TEST [SPEC]||HESS PUMICE|
|Organic Impurities||ASTM C40 [Hellige #3]||Lighter than #1|
|Staining||ASTM C641 [No Staining]||Stain Index = 0|
|Clay Lumps and Friable Particles||ASTM C142 [5% max]||0%|
|Bulk Density: Loose, Fine Aggregate||ASTM C29 [70 lbs/cf max]||49 lbs/cf|
|Concrete Density||ASTM C567 [100 lbs/cf max]||89 lbs/cf|
|Compressive Strength||ASTM C39 [2500 PSI min]||2454 PSI|
|Splitting Tensile Strength||ASTM C496 [290 PSI min]||290 PSI|
|Drying Shrinkage||ASTM C157 [0.07% max]||0.01%|
|Popouts||ASTM C151 [No Popouts]||No Popouts|
|PROPERTY:||1/8 FINES MN|
|Dry Loose Unit Weight||49 lbs/cf|
|Bulk Specific Gravity||1.59|
|S.S.D. Specific Gravity||1.84|
About Hess Pumice Co.
For more than six decades, Hess has been extracting and refining pumice from our southeast Idaho deposit. The incredible versatility of our pumice has spurred us to develop pumice grades and grade blends to fit a variety of industrial processes and consumer product formulations. We actively seek new frontiers and have even built new markets for pumice.
Comprehensive information about Hess Pumice Co., the grade varieties we produce, and the wide and diverse applications for our pumice can be found at hesspumice.com