A review of the classification of opal with reference to recent new localities
Our examination of over 230 worldwide opal samples shows that X-ray diffraction (XRD)
remains the best primary method for delineation and classification of opal-A, opal-CT and …
remains the best primary method for delineation and classification of opal-A, opal-CT and …
Siliceous sinters in thermal spring systems: Review of their mineralogy, diagenesis, and fabrics
B Jones - Sedimentary Geology, 2021 - Elsevier
This paper provides a comprehensive review of the sinter deposits, formed largely of opal-A,
that are form around hot springs and geysers throughout the world. The discharge aprons …
that are form around hot springs and geysers throughout the world. The discharge aprons …
Naturally organic functionalized 3D biosilica from diatom microalgae
The diatom biosilica was produced by cultivation of the selected species of diatoms
(Pseudostaurosira trainorii) under laboratory conditions. The morphological and structural …
(Pseudostaurosira trainorii) under laboratory conditions. The morphological and structural …
[HTML][HTML] Electrochemical behavior of a composite material containing 3D-structured diatom biosilica
Abstract 3D-structured diatom biosilica mixed with conducting carbon black was investigated
as an active electrode material for lithium-ion batteries. Diatom biosilica was obtained by …
as an active electrode material for lithium-ion batteries. Diatom biosilica was obtained by …
Hydrothermal genesis and growth of the banded agates from the Allumiere-Tolfa volcanic district (Latium, Italy)
A Conte, G Della Ventura, B Rondeau… - Physics and Chemistry …, 2022 - Springer
In this work, we studied the hydrothermal agates from the Neogene–Quaternary volcanic
district of Allumiere-Tolfa, north-west of Rome (Latium, Italy) using a combination of micro …
district of Allumiere-Tolfa, north-west of Rome (Latium, Italy) using a combination of micro …
Preparation, characterization, and performance of 4A zeolite based on opal waste rock for removal of ammonium ion
In this study, 4A zeolite was prepared from opal waste rock by hydrothermal method and
applied in ammonium ion adsorption. To optimize synthesis conditions, the effect of …
applied in ammonium ion adsorption. To optimize synthesis conditions, the effect of …
Effective cesium removal from Cs-containing water using chemically activated opaline mudstone mainly composed of opal-cristobalite/tridymite (opal-CT)
S Kwon, Y Kim, Y Roh - Scientific Reports, 2021 - nature.com
Opaline mudstone (OM) composed of opal-CT (SiO2· n H2O) has high potential use as a
cesium (Cs) adsorbent, due to its high specific surface area (SSA). The objective of this …
cesium (Cs) adsorbent, due to its high specific surface area (SSA). The objective of this …
Volcanic SiO2-cristobalite: A natural product of chemical vapor deposition
Cristobalite is a low-pressure, high-temperature SiO2 polymorph that occurs as a metastable
phase in many geologic settings, including as crystals deposited from vapor within the pores …
phase in many geologic settings, including as crystals deposited from vapor within the pores …
[HTML][HTML] Microstructures in shocked quartz: linking nuclear airbursts and meteorite impacts
RE Hermes, HR Wenk, JP Kennett… - Airbursts and …, 2023 - scienceopen.com
Many studies of hypervelocity impact craters have described the characteristics of quartz
grains shock-metamorphosed at high pressures of> 10 GPa. In contrast, few studies have …
grains shock-metamorphosed at high pressures of> 10 GPa. In contrast, few studies have …
Near infrared signature of opal and chalcedony as a proxy for their structure and formation conditions
B Chauviré, B Rondeau… - European Journal of …, 2017 - pubs.geoscienceworld.org
Opal-A, opal-CT and chalcedony develop in various geological environments mainly
through continental weathering and hydrothermal processes. Although some spectroscopic …
through continental weathering and hydrothermal processes. Although some spectroscopic …