Birthstones are a fun, popular and colorful introduction to the world of gemstones. They appeal to audiences around the world regardless of gender, age, nationality or religion. Birthstones carry ...

Get expert, comprehensive analysis of your jewelry items. These services include assessments of natural D-to-Z diamonds, offering details such as estimated total carat weight, color and clarity ranges ...

Explore diamond history, research, quality factors, and more in the GIA Gem Encyclopedia.

Major rock units of the Neyshabur mine are divided into three groups: volcanic, subvolcanic intrusions, and hydrothermal breccia (Ghiasvand et al., 2017). Although the volcanic rocks of trachyte and ...

This 32” x 20” wall chart presents GIA’s system for classifying pearl quality according to the seven factors of size, shape, color, luster, surface, matching, and nacre.

GIA does not certify or appraise any material submitted for analysis. GIA reports (not certificates) offer technical information on the dimensions, quality and identifying characteristics of a diamond ...

Explore pearl history, research, quality factors, and more in the GIA Gem Encyclopedia.

GIA doesn’t grade or provide quality analysis for sapphire or other colored stones. GIA Gemological Identification Reports assess the characteristics of a stone (weight, measurements, shape, cutting ...

Touchstone method There are a few scientific methods for precisely determining karat gold purity, some destructive (fire assay) and others nondestructive (X-ray fluorescence). Both methods require ...

Another way to measure a ring is to take a measurement of the inside and determine the finger size from a standard chart. The inside of the ring must be perfectly round for this to work.

As part of this service, a gold bracelet measuring 8 inches in circumference and 1.25 inches wide and weighing 41 g was recently examined in the Carlsbad laboratory (figure 1). It was submitted as 14K ...

A synthetic gem material is one that is made in a laboratory, but which shares virtually all chemical, optical, and physical characteristics of its natural mineral counterpart, though in some cases, ...