0 a hard, transparent mineral substance, used in making electronic equipment and accurate watches and clocks
1 a mineral (= hard substance formed naturally in the ground) used in making electronic equipment and watches and clocks
A pure quartz reagent blank and several certified geological reference standards, as well as internal laboratory standards, were analysed with these samples.
It is typically defined by the shapepreferred orientation of mica and elongated quartz grains.
The vesicles are filled with calcite, chlorite, quartz and carbon.
Furthermore, both the tube and the coil are surrounded by the tube cooling, which protects the quartz tube from overheating.
The c. 25 m of purple, fine-grained sandstones below include quartz-arenitic intercalations and have an essentially calcareous matrix.
Other alteration products are chlorite, sericite, quartz and opaque minerals.
The newly crystallized quartz grains are characterized by elongate crystals oriented oblique to the shear band margins, defining a typical grain-shape foliation.
The presence of quartz-filled microcracks in feldspar crystals suggests that deformation continued during cooling and crystallization.
