Minerals can be divided into two main categories, 1) macro-minerals and 2) micro or trace minerals. Macro minerals are minerals that are needed/required in relatively large amounts in comparison to micro or trace elements which are needed/required in relatively small amounts. In general macro minerals are required at concentrations greater than 100 ppm of the diet and are often expressed as a p...

The prebiotic significance of laboratory experiments that study the interactions between oligomeric RNA and mineral species is difficult to know. Natural exemplars of specific minerals can differ widely depending on their provenance. While laboratory-generated samples of synthetic minerals can have controlled compositions, they are often viewed as "unnatural". Here, we show how trends in the in...

More than half of the >5000 approved mineral species are known from five or fewer localities and thus are rare. Mineralogical rarity arises from different circumstances, but all rare mineral species conform to one or more of four criteria: (1) P-T-X range: minerals that form only under highly restricted conditions in pressure-temperature-composition space; (2) Planetary constraints: minerals th...

a study was conducted to evaluate the effect of feeding different levels of protein to black baladi breed kids. weanling baladi kids (n=18; 75 to 90 days old) were selected and individually housed at our experimental farm. kids were divided randomly to one of the three treatments for 12 weeks. the three dietary treatments were: t1: control ration, formulated according to nrc to cover the protei...

this study investigated the relationship between clay minerals and different soil moisture regimes in gypsiferous soils of fars province in southern iran. the overall climate of the province is arid and semi-arid and, under this condition, parent material is the most important factor affecting clay minerals distribution. beside this factor, climate conditions have determining role too. palygors...

X-ray phase analysis of clays is difficult because these materials generally consist of a mixture of different phases, i.e., mixed-layer minerals, individual clay minerals (non mixed-layer), and associated minerals, such as calcite and quartz. The analysis requires knowledge that presently is incorporated in a computer-based expert system. This expert system is capable of a) identification of a...

The lunar rocks described in the next chapter are unique to the Moon. Their special characteristics— especially the complete lack of water, the common presence of metallic iron, and the ratios of certain trace chemical elements—make it easy to distinguish them from terrestrial rocks. However, the minerals that make up lunar rocks are (with a few notable exceptions) minerals that are also found ...

Rare earth elements (REE) are either housed in exotic REE minerals that sporadically populate the host rock or they occur as ionic substitutions in the crystal structure of existing rock-forming minerals. The genesis of REEs in carbonatite rocks can result in intricate mineralogical textures between REE minerals, host rock minerals, and minerals formed by later processes. Upfront mineralogical ...

We present a first paragenetic study of the Wuyier, Wuyisan, Wuyiyi and Shihongtan sandstone-hosted roll-front uranium deposits, northwest China. The mineralization is hosted by Lower–Middle Jurassic coarseto medium-grained sandstones, which are dark-gray to black due to a mixture of ore minerals and carbonaceous debris. The sandstone is alluvial fan-braided river facies. Minerals associated wi...