siliceous

The researchers found that while a vast majority of the minerals that make up ash are highly reactive and soon decay, about two percent by volume are made up of a stable group of minerals called siliceous aggregates.

Quest for Ash 1997

Consolidation through the concretion of substances dissolved in the sea is unlikely, for, in the first place, there are strata, such as siliceous matter, which are insoluble, and which could not therefore have been in solution; and, in the second place, the appearance of the strata is contrary to this supposition.

The World's Greatest Books — Volume 15 — Science Various 1909

Diatoms have non-growing siliceous shells and thus need silicate for growth while dinoflagellates move by the action of tail-like projections called flagella.

General description of the Arctic biota 2009

These are free crystalline silica known to cause silicosis, a disabling and potential fatal lung disease typically found in miners and quarry workers exposed to high concentrations of siliceous dust over long periods of time.

Volcanic Ash -- Effects on Health and Mitigation Strategies 2009

These are free crystalline silica known to cause silicosis, a disabling and potential fatal lung disease typically found in miners and quarry workers exposed to high concentrations of siliceous dust over long periods of time.

Volcanic Ash -- Effects on Health and Mitigation Strategies 2009

Alpine bedrocks can be divided into two major groups: calcareous rocks and siliceous material.

Alps conifer and mixed forests 2009

In general, the best biological indicators are those with good preservation potential, for example, siliceous, chitinized, or (under neutral to alkaline pH conditions) carbonaceous body parts.

Historical changes in freshwater ecosystems in the Arctic 2009

Gently sloping sand plains of medium textured red earths, sandy loams and red earth sands are separated from dune formations of red siliceous sand and red earth sands by a transitional zone comprising largely very coarse siliceous sand.

Uluru-Kata Tjuta National Park, Australia 2008

These stones are more sensitive to acid than siliceous ones.

Protect Your Investment: Stone Countertops 2008

Heath forest is found on well-drained acidic soils (pH lass than 4) with a low clay content, derived from siliceous rocks under ever-wet conditions.

Sundaland heath forests 2008