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page title: pumice vs. X (furnace-expanded, pumice-like materials)

Imitation of the usefully exquisite is inevitable. Pumice, for example. There are a handful of pumice-like materials on the market, touting the same highly versatile, widely useful foamed-stone form factor. What is not pumice-like about them? Their kiln-fired, man-made genesis.

Widely Useful Form Factor

Pumice is not, of course, the de facto best solution for every specialized use claimed by the pumice-like products, but pumice has direct application—or unexplored potential—for most uses, and in many cases, exceeds the performance of the made-alike product. And the fact that pumice does not need the furnace treatment provides industry with a widely useful product featuring these advantages:

1) Impressive grade range. Because of the elemental-scale genesis of pumice, that frothy, glassy, amorphous character is infused all the way down to the microscopic level. And that means even powdery grades hold true to functional form.

2) Price economy, especially in by-the-ton mine grades—pumice needs only to be mined, crushed, and screened to grade. Even when purchasing pumice for uses that demand further refinement (tight grade tolerances, fine- and micro-grade powders, blended grades, non-pumice/pumice heavies removal, packaging), pumice shapes an attractive cost curve.

3) Sustained, wide-stream production, without the furnace bottleneck. Mine, crush, screen, ship—all volume-production processes.

4) Green credibility. No fuel burn, no fire, no carbon compounds released.

Pumice vs. Expanded Perlite

Perlite ore is dense, glassy and rich with trapped moisture. Mined, crushed to grade, and sent through a flash-heating expansion furnace, perlite ore pops to form little lightweight particles—each a bright-white, fluffy matrix of tiny fused bubbles. Expanded perlite grades are determined by the pre-expansion crush of the ore, but expanded perlite can be further processed/crushed into microscopic shards, which broadens perlite’s application-range.

Pumice is the physiochemical equivalent of expanded perlite and delivers similar functionality.01 There are applications where pumice does not provide equivalent utility and performance, primarily in insulative uses, but in most cases, especially in perlite’s horticultural applications, pumice absolutely delivers the desired performance. This physicochemical equivalency runs true—even out-preforms in key areas—in applications such as potting soil blends, soilless grow media, amending poor native turf, garden, or reclamation soils, and insulative concrete.

Pumice vs. Expanded Clay

Lightweight Expanded Clay Aggregate (LECA) was initially developed for use as a lightweight construction aggregate, with some function as a filtration media. In its rounded pebble form, expanded clays have found use as a soilless grow media.

In each of the above areas, pumice is also used. Pumice makes an excellent soilless grow media02, and the grade-versatility of pumice allow the grower to really dial in the media to fit the system and the plant type. Pumice is also an excellent soil amendment, improving both the friability of the rootzone and the drainage/moisture-holding function when blended with poor native soils.03

Pumice vs. Expanded Shale and Slate

Like expanded clay aggregates, expanded shale and slate products are used primarily in horticulture and as lightweight construction aggregates. Especially in materials-hungry construction applications, the economy + performance combination make pumice an excellent choice.

Pumice vs. Recycled Foamed Glass

Foamed glass aggregate products seek attention using high-concept monikers such as “urban mining:” taking waste glass and making something new and useful. Recycling is a use-beaten path that has delivered results; it’s also delivered a lot of expensive solutions. The cost can be sometimes justified in process savings, disposal savings, or sourcing savings. In other instances, the higher cost to reuse and repurpose is embraced as a sort of philanthropy. On the plus side, glass is removed from the waste stream and repurposed. On the minus side is the process itself: the costs (in money and energy burn) to gather, transport, crush, mix with a foaming agent, and kiln-fire the powder to its useful state.

Recycled foamed glass products are available in the same spaces as expanded perlite, shale, and clay—horticulture—and also in the lightweight aggregate space.

Pumice vs. Vermiculite

Finished vermiculite is made via heat-expanding vermiculite ore.04 Known primarily for its horticultural applications, exfoliated vermiculite also has some industrial and construction applications. It is quite soft and crumbly, rating a 1.5 to 2 on the Mohs hardness scale.

Pumice weighs in on the Mohs hardness scale at a 6, making it an excellent abrasive, but also more stable and rigid than vermiculite, hence is an excellent filler for lightweight stuccos and mortars, spray-on concretes, and form-cast concrete products. Pumice is absorptive, yet it does not get soggy; friable, but not soft. When used as a soil amendment, pumice does not break down or compact, rather it stays securely anchored in the soil matrix and retains its functional form indefinitely.

Sourcing Pumice

Hess Pumice Products provides pumice to market at two levels: industrial-use quantities shipped via rail, truck, or ocean container, and small quantities for specific consumer-direct uses via an online Pumice Store backed by a dedicated fulfillment center.


Hess produces a variety of pumice grade and grade blends, from one-inch aggregate to highly refined powders as small as 3 microns. Email salesteam@hesspumice.com (or call 208.766.4777) for expert help with grade selection and logistics.


Sample most of our production grades or purchase branded pumice products for specific applications via an online ordering process.