Applications of Petrography

Petrographic examination of suites of potsherds can help classify them based on the composition and texture of the rock and mineral particles added to clay for strengthening the product. Such a classification can be used with archaeological studies on form, types of glazing, and other cultural characteristics to help distinguish pottery from different sources. In some cases, the suite of materials added is characteristic of a certain geographical region, so specific source areas can be identified which could indicate ancient trade routes. Petrographic examination of materials suspected to be from ancient buildings, stelae, or other artifacts can be compared with materials from suspected source areas. If these are similar, one could conclude that the material in question did indeed come from the suspected source area or a geologically very similar and probably closely spatially related source area.

Examination of source materials of feldspar and nepheline syenite for possible use in the ceramic and glass industries. The examination determines the amounts of deleterious minerals and their textures, and comments on whether they can be easily separated by simple methods (e.g. magnetic separation).

Petrographic and x-ray diffraction analysis are used to identify and classify clay minerals.

Field geological studies of potential quarry sites or active quarries help determine the suitability of the material for production of aggregates, and will identify any problem areas in the quarry (strong joint and fracture zones, dikes, alteration zones) that need to be avoided or separated before the aggregate is prepared. Field Geological Studies Field geological studies of potential quarry sites or active quarries help determine the suitability of the material for production of aggregates, and will identify any problem areas in the quarry (strong joint and fracture zones, dikes, alteration zones) that need to be avoided or separated before the aggregate is prepared. Aggregate Analysis (according to ASTM Standard Test C-295) This analysis is used to determine the suitability of aggregate for use in concrete or road or dam ballast. The analysis reports on the distribution of shapes, sizes, and expected reactivity of aggregate particles, classifies them petrographically, examines coatings on aggregate particles, and comments on any deleterious material present in the sample. Porosity Analysis (according to ASTM Standard Test C-457) This analysis examines the abundance, sizes, and shapes of pores in hardened concrete according to recognized industry parameters. Problems related to abrasion or unusual wear of concrete Petrographic examination helps to understand and explain problems related to concrete wear through chipping, flaking, and other types of degeneration as a result of acid leaching, chemical reactions between particles and cement, and physical wear.

Field Mapping and assessment of mineral potential in most geological environments both in North America and other countries. Expertise can be provided in solving problems related to ore deposits, structural geology, petrology, regional geology, geochemistry and deposits of industrial minerals.

Petrographic examination of source rocks and crushed material to determine the abundance, grain size, and texture of graphite, and the suitability of source materials for production of commercial grade graphite concentrates.

Samples are processed in two stages: Stage 1: Hand-sorting of indicator minerals. Note that diamond indicator-minerals are hand-sorted at Vancouver Petrographics Ltd. from heavy-mineral concentrates received from the Process Research Associates. Stage 2: Grains picked are catalogued, mounted on slides and polished to electron probe analysis specifications. Indicator Minerals include Pyrope Garnet, Magnesian ilmenite, Chrome Diopside and Chromite and other minerals. Indicator minerals are hand-picked using established picking techniques. The number of grains are counted for each sample and entered into the database. Depending upon the objective of the project, coarsest fractions are generally chosen for hand-sorting of minerals. Scanning Electron Microscope/Electron Probe Analysis Based on the interest of the client, this analysis can be done at reasonable rates. Rates will depend on mineral type and number of grains to be analyzed.

The content of water-soluble clay minerals in many kimberlites make them very difficult to preserve in thin sections. Vancouver Petrographics has developed methods that produce a 99% success rate for this type of sample. We can produce super-thin, 10-20 Micron, slightly wedged sections, commonly referred to as the "Scott-Smith style", that many geologists find useful to help identify diagnostic minerals in highly altered kimberlites.

Meteorite composition can be determined through careful examination of a prepared sample.

Examinations are made of source materials and products of materials such as rutile and wollastonite to determine their suitability for use in the paint and related industries. Studies examine textures regarding clarity of materials and their ease of separation from the host rock, degree of purity of products, and aspect ratios (for wollastonite).

Petrographic examination of source rocks and crushed material to determine the suitability for fill. Analysis includes petrographic analysis, determination of size-and shape-distribution of crushed materials, identification of deleterious components (e.g., sulphides, water-soluble materials).