Calcite bright

Helderberg carbonates are extensively cemented by clear equant calcite cement that postdates marine cement and fills most of the original pores. These cements are compositionally zoned as shown by cathodoluminescence and trace element analyses. These precipitates include nonluminescent, bright and dull cements. The luminescent cement is the earliest generation of cement followed by... 

Figure 1.11. TEM images of the calcite single crystal shocked in a laser irradiation experiment with an initial pressure of 225 GPa. (a) Dark-field TEM image of a 60-gm-deep zone in the specimen, containing numerous dislocation loops. This microstructurc indicates incipient decomposition, (b) Dark-field TEM image of tangled, curved dislocations occurring in a depth of 90 pm below the initial specimen surface, (c) Bright-field TEM image of a multiply twinned zone in a depth of 280 pm.

Faience Non-clay based ceramic, made from sand, salt (natron), calcite lime, and various mineral pigments, displaying surface vitrification which results a bright luster. 

Fig. 3. Pre-quartz, early calcite. Back-scattered electron images. Scale bars 100 pm. (A) Early calcite (c) that postdates early siderite (bright rhombs) KY64A.

Some minerals emit a bright, often colored light (e.g., fluorescence and phosphorescence) when heated below redness, that is, above SOO C. The effect can be observed only in darkness. It is caused by the relaxation of lattice defects upon heating. The lattice defects are always due to radiation dammage that the crystal undergoes since its formation. This effect is called thermoluminescence, it is often found on fluorite, quartz, calcite, apatite, zircon, and diamond. 

Fig. 3. Dislocations in carbonates (a) Dark-field TEM image showing dislocations and stacking faults on the <2 i i 0) planes generated by basal slip in a dolomite single crystal deformed at 420°C [52]. (b) Dislocations associated with crossing mechanical twins in calcite (TEM, bright field) [161].

---