Gemstone Information

Enhancement is defined as any treatment process other than cutting and polishing that improves the appearance, durability, or availability of a gemstone. A large portion of colored gemstones on the market today have undergone some form of treatment. These enhancement processes are permanent, stable and safe, and do not affect the quality and in most instances the value of the gemstone. In fact, often with such enhancement processes, like heating, the natural beauty of the stone is much improved. We will make note of any stone treated by a non-industry accepted manner or if the treatment or process is not permanent.

The AGTA Gemstone Enhancement Manual and the AGTA Gemstone Information page as both have an extensive list of gems, their common enhancements, and durability of enhancements. In posting these informative links we are not implying an association or membership with the AGTA but suggesting them as informational references.

Gemstone Quality

Amethyst

Quartz, hardness of 7, natural stones which are not currently known to be enhanced.

AAA = Eye clean, deep purple, little or no color zoning, good cut.

AA = Eye clean, medium / medium dark purple, little or no color zoning, good cut.

A = Eye clean to slight imperfections, light to medium purple, little or no color zoning, good cut.

Aquamarine

Beryl, 7.5 to 8 hardness, the use of heat to effect desired alteration of color and clarity.

AAA = Eye clean, medium to medium dark color, good cut.

AA = Eye clean, light to medium color, good cut.

A = Included, light color, good cut.

B = Included, very light color, good cut.

Citrine

Quartz, 7 hardness, the use of heat to effect desired alteration of color and clarity.

AAA = Eye clean, medium gold to slightly orange, little or no color zoning, good cut.

AA = Eye clean, medium golden yellow, little or no color zoning, good cut.

A = Eye clean, light slightly golden yellow, little or no color zoning, good cut.

Diamond

Natural stones which are not currently known to be enhanced.

SI/GH = SI-2 clarity, slightly included, small inclusions somewhat easy to see with a 10x loupe, G to I in color, good cut, good polish.

I-1/GH = I-1 clarity, inclusions can be seen with the unaided eye, G to I in color, good cut, good polish.

Garnet, Mozambique

Pyrope, 7 to 7.5 hardness, natural stones which are not currently known to be enhanced.

AA = Eye clean, medium /dark, red/orange brown, good cut.

Garnet, Rhodolite

7 to 7.5 hardness, natural stones which are not currently known to be enhanced.

AA = Eye clean, medium / dark, raspberry to plum, good cut.

Moissanite

9.25 hardness, man made / lab created.

Slightly tinted yellow (I-K in color), good cut, very high dispersion.

Peridot

6.5 to 7 hardness, natural stones which are not currently known to be enhanced.

AA = Eye clean, medium to dark slightly yellowish green, good cut.

Sapphire

Corundum, 9 hardness, the use of heat to effect desired alteration of color and clarity.

Top blue =Eye clean, medium to dark navy blue, no color zoning, excellent brilliance, excellent cut.

AA = Eye clean, medium, navy to royal blue, little to no color zoning, good brilliance, good cut.

A = Slightly included, medium to dark navy, little or no color zoning, good cut.

B = Slightly included, medium dark navy, good cut, good polish, little to no color zoning.

Commercial - Slightly included, dark navy, may have color zoning, good cut.

Topaz, Sky Blue

8 hardness, irradiated and may be followed by a heating process.

AA = Eye clean, bright light blue, good brilliance, good cut, good polish.

Topaz, London Blue

8 hardness, irradiated and may be followed by a heating process.

AA = Eye clean, grayish blue medium / dark, good brilliance, good cut, good polish.

Topaz, Mystic

8 hardness, treated through the use of such surface enhancement as sputtering of films to provide color.

Mystic topaz begins as clear, white topaz. It undergoes a process called vacuum deposition, where a titanium coating is applied permanently to the pavilion (back of the gem). The coating is difficult to scratch, it is however protected by the setting.

Green aka peacock, AA = Medium light green with purple and pink hues.

Pure pink, AA = Medium to medium dark vibrant pink.

Sunrise, AA = Medium light orangey yellow with pink hues.

Poppy, AA = Medium dark orange, good cut.

Tourmaline

The use of heat to effect desired alteration of color and clarity.

Green, A quality - Eye clean to slight imperfections, medium light to dark yellowish green, good cut.

Pink, AA quality - Slightly included to eye clean, medium to medium dark pink, good cut.

Quartz

Irradiated and may be followed by a heating process.

Lemon, AA quality - Eye clean, light slightly greenish yellow, good cut, good polish.