Gem news from GIA Dec 2025
Extraordinary Large Bicolor Natural Rough Diamond
October 15, 2025
Rough pink diamonds are rarely found, and although the cause of color has been correlated with plastic deformation, the precise mechanism and atomic configuration for the resulting color are topics of continuous research. Therefore, when GIA receives a diamond with distinct pink and colorless sections (figure 1), it is of scientific interest, particularly at an astounding weight of 37.41 ct. GIA has previously examined comparable type Ia pink and colorless bicolor rough, both reportedly from Australia, in much smaller specimens weighing less than 2 ct each Read the full article here
Quarterly Crystal: Almandine-Pyrope Garnet in Diamond
John I. Koivula and Nathan Renfro
The authors recently examined a collection of African diamond crystals that hosted various mineral inclusions. This Quarterly Crystal, chosen from that collection, is a 2.34 ct transparent near-colorless partially etched diamond octahedron measuring 7.71 × 7.39 × 4.92 mm, which came from the Republic of South Africa (figure 1). During routine testing, the near-colorless octahedron fluoresced a strong blue when exposed to long-wave (365 nm) ultraviolet radiation.
The diamond crystal hosts a transparent yellow-orange inclusion situated near its center. Laser Raman microspectroscopy identified this included crystal as an almandine-pyrope garnet. The yellow-orange color is typical of this type of inclusion. In addition to the garnet, light grayish green transparent birefringent omphacite crystals and opaque black sulfide and graphite crystals (some forming rosettes) were also present.
This guide examines the world of gem and jewelry appraisals, equipping you with the knowledge to navigate this process with confidence. We’ll explore:
The Purpose of Appraisals: Understanding the different reasons why you might need an appraisal.
Gemstone Identification and Valuation: Delving into the factors that determine a gem’s value.
Understanding Provenance: Exploring how a piece’s history can add value.
The Appraisal Process: What to expect from a professional appraisal.
Finding a Qualified Appraiser: Identifying reputable appraisers with the necessary expertise.
Types of Appraisals: Distinguishing between replacement value, fair market value, and others.
Beyond Diamonds: Appraising colored gemstones, pearls, and other materials.
Contact American Gem Registry for an appointment
Schedule an Appointment for your Appraisal
By Appointment Only.
5610 Ward Rd #300
Arvada, CO 80002
neil@gemlab.us
303-223-4944
Your use of this email constitutes agreement to be contacted regarding your query only.
Offices Located in Arvada, Colorado
My office is located in Arvada, Colorado, a suburb of Denver, but I have many customers in the surrounding suburbs and even states! It’s worth the drive from as far as Cheyenne, WY, Colorado Springs, or even Pueblo for an independent appraisal.
I have top qualifications, I charge reasonable and transparent prices, and I do the work while you wait and while you watch if you like.
This guide examines the world of gem and jewelry appraisals, equipping you with the knowledge to navigate this process with confidence. We’ll explore:The Purpose of Appraisals: Understanding the different reasons why you might need an appraisal.
Gemstone Identification and Valuation: Delving into the factors that determine a gem’s value.
Understanding Provenance: Exploring how a piece’s history can add value.
The Appraisal Process: What to expect from a professional appraisal.
Finding a Qualified Appraiser: Identifying reputable appraisers with the necessary expertise.
Types of Appraisals: Distinguishing between replacement value, fair market value, and others.
Beyond Diamonds: Appraising colored gemstones, pearls, and other materials.
Contact American Gem Registry for an appointment
Schedule an Appointment for your Appraisal
By Appointment Only.
5610 Ward Rd #300
Arvada, CO 80002
neil@gemlab.us
303-223-4944
Your use of this email constitutes agreement to be contacted regarding your query only.
Offices Located in Arvada, Colorado
My office is located in Arvada, Colorado, a suburb of Denver, but I have many customers in the surrounding suburbs and even states! It’s worth the drive from as far as Cheyenne, WY, Colorado Springs, or even Pueblo for an independent appraisal.
I have top qualifications, I charge reasonable and transparent prices, and I do the work while you wait and while you watch if you like.
This guide examines the world of gem and jewelry appraisals, equipping you with the knowledge to navigate this process with confidence. We’ll explore:The Purpose of Appraisals: Understanding the different reasons why you might need an appraisal.
Gemstone Identification and Valuation: Delving into the factors that determine a gem’s value.
Understanding Provenance: Exploring how a piece’s history can add value.
The Appraisal Process: What to expect from a professional appraisal.
Finding a Qualified Appraiser: Identifying reputable appraisers with the necessary expertise.
Types of Appraisals: Distinguishing between replacement value, fair market value, and others.
Beyond Diamonds: Appraising colored gemstones, pearls, and other materials.
Contact American Gem Registry for an appointment
Schedule an Appointment for your Appraisal
By Appointment Only.
5610 Ward Rd #300
Arvada, CO 80002
neil@gemlab.us
303-223-4944
Your use of this email constitutes agreement to be contacted regarding your query only.
Offices Located in Arvada, Colorado
My office is located in Arvada, Colorado, a suburb of Denver, but I have many customers in the surrounding suburbs and even states! It’s worth the drive from as far as Cheyenne, WY, Colorado Springs, or even Pueblo for an independent appraisal.
I have top qualifications, I charge reasonable and transparent prices, and I do the work while you wait and while you watch if you like.