Thuật ngữ khoáng vật học
Các thuật ngữ và định nghĩa thiết yếu cho khoáng vật học và sưu tập khoáng vật.
Gemology
Brilliance
The white light returned from the interior and surface of a faceted gemstone to the …
Carat
The unit of weight for gemstones, equal to 0.2 grams. One carat is divided into …
Fire
The display of spectral colors (red, orange, yellow, green, blue, violet) produced by the dispersion …
Crown
The upper portion of a faceted gemstone, above the girdle. Crown height and angle affect …
Loupe
A small magnifying lens used by gemologists to examine stones. Standard gem loupes are 10× …
Table
The largest and topmost flat facet on a faceted gemstone. The table percentage (table width …
Facet
A flat, polished surface deliberately cut on a gemstone to reflect and refract light. The …
Girdle
The narrow band around the widest part of a faceted gemstone, separating the crown from …
Cabochon
A gemstone cutting style producing a smooth, domed top and flat or slightly convex back, …
Inclusion
Any internal feature within a gemstone, including crystals, needles, clouds, feathers, or growth irregularities. Inclusions …
Pavilion
The lower portion of a faceted gemstone, below the girdle. The pavilion angle is critical …
Dispersion (Gem)
The difference in refractive index between red and violet light in a gemstone, quantified as …
Refractive Index (Gem)
A key gemological property measured with a refractometer to help identify gem species. Values range …
Chatoyancy (Gem)
The mobile bright band seen in cat's-eye gems such as chrysoberyl cat's-eye, caused by reflection …
Pleochroism (Gem)
The display of different colors in different crystallographic directions, important in gem cutting decisions. Tanzanite …
Color Zoning
Uneven distribution of color within a gemstone, often in distinct bands or patches reflecting growth …
Treatment
Any process applied to a gemstone to improve its appearance or durability after mining. Common …
Cut Grade
An assessment of how well a gemstone has been fashioned, evaluating proportions, symmetry, and polish. …
Asterism (Gem)
The star-shaped optical phenomenon in star rubies, star sapphires, and star garnets, caused by oriented …
Clarity
A grading measure of the absence of inclusions and blemishes in a gemstone. The GIA …