In the blue region of the photoluminescence spectrum of calcite crystals obtained from Siberia (Russia) and from Saaremaa Island (Estonia), three strongly overlapping luminescence bands due to intrinsic defects are observed. Luminescence due to impurities in the crystals are hardly detectable. The ...
It is generally agreed that chalcedony is aquartz gemcomposed of very small crystals which cannot be distinguished with a loupe or a standard gemmological microscope. Most types, such as chalcedony, agate, and jasper are included in this description but coarser grained varieties, such as aventurine...
Occasionally minerals can grow within rocks into shapes resembling fossils, but they aren't fossils. An example is dendrite crystals, which are often mistaken for fernlike fossils. Concentrations of minerals in sediments are sometimes mistaken for eggs that have been fossilized. Also, modern plants ...
CALCITE CRYSTALSINHIBITIONCITRATEInteractions between different types of additives with specific crystal surfaces of mineral phases found in biominerals were investigated at nanometer and micrometer scales by in situ atomic force microscopy (AFM). Firstly, the inhibitory effect of magnesium ion (Mg2+) ...
Reduction of the TCLP-Pb might result from complexation of Pb on the surface of the formed calcite. High pH would enhance adsorption of Pb on the calcite surface. Immobilization may also be associated with the formation of calcium silicon hydrates and calcium aluminum hydrates and ettringite with...
At 55 °C, aragonite dominates and the content of calcite increases with time in the bulk solution, and distorted calcite and flowerlike aragonite The saturation state of the test brines with respect to CaCO3 (calcite) was calculated using the SI17: dominate on the surface. The researchers ...
Mg and Ca. The XPS characterization technique further validates the result obtained from XRD analysis. Though carbonates are considered to be primarily composed of calcites, Mg-calcite and dolomites, presence of Si impurities might affect the conventional mineralogical properties of the crushed carbonate...
In addition, it was established that on the surfaces previously scaled with calcite, crystals initially formed in the damage process act as growth sites causing the continuation of scale at the expense of ionic concentration of a new solution. Moreover, due to such growth and hydrodynamic ...
2) Black olivine-rich basalts which are present in the topmost part of harrat Al Fatih are generally black, hard and contain remarkable reddish brown oxidized olivine spots and some calcite and amorphous quartz domains. Under the microscope, this basalt type is microcrystalline and composed mainly ...