Guide to Reading Gemports
The Gemports Colored Gemstone price report reference document serves as a crucial tool for industry stakeholders worldwide. As a co-creator, the Thai Gem and Jewelry Traders Association (TGJTA) is committed to promoting transparency and establishing internationally recognized standards. This guide has been created to ensure the report can be applied to its fullest potential.
1. Detail of the Report (Structure and Key Elements)
Understanding each component of the report is the primary step to using it with maximum accuracy
(Sample Gemports Report Table – Ruby and Blue Sapphire)
1.1 Reference Date: The report clearly specifies the quarter and year of the data, which is divided into four quarters
· Q1: January 1 – March 31
· Q2: April 1 – June 30
· Q3: July 1 – September 30
· Q4: October 1 – December 31
1.2 Gemstone Type & Origin: The report categorizes by gemstone type (e.g., Ruby, Sapphire) and provides sub-tables based on origins that significantly impact value:
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Ruby: Categorized into two origins: 1. Myanmar, 2. Africa and Other Sources. Currently, Myanmar rubies command higher prices.
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Sapphire: Categorized into two origins: 1. Sri Lanka, Africa and Other Sources. Currently, Sri Lanka sapphires command higher prices.
1.3 Weight Category: The tables display the price per carat for standard weight ranges, which vary by report. For instance, rubies range from 1 to 10.00 carats, while sapphires range from 1 to 20.00 carats. For weights exceeding those listed in the table, a "Negotiate Price" applies.
1.4 Treatment: The reports clearly distinguish between "Nature" (untreated) and "Heat" (enhanced by heat, no residues present).
1.5 Price per Carat: Displayed in the specific currency per carat (USD, CNY, or THB/ct.).
1.6 Color: The color group of the Ruby or Sapphire is a crucial factor that differentiates the gemstone's value.
1.7 Criterion-Referenced: The prices referenced in this table are based on gemstones that are "eye clean," feature good cutting proportions, and are oval-shaped.
2. Step-by-Step Guide to Price Evaluation
Example 1: Ruby Price Calculation
We want to find the price of an Oval Ruby, 2.5 carats, Intense Red, Myanmar origin, Nature (untreated), in Q4 2025.
Step 1: Select the table: "MYANMAR: (1.00-10.00 CT): Q4 2025".
Step 2: Find the reference price per carat.:
For a 2.5 ct Ruby, look at the 2-2.99 ct range. Since it is untreated, select the "Nature" column. For an Intense Red color, select the "Intense Red" row. The resulting reference price is 48,130 USD/ct.
Step 3: Calculate the value by substituting the numbers into the formula
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Price per Carat
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Ruby Weight in Carats
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Exchange Rate (Currency) / USD – If currency conversion is not required, please leave this field blank.
= 48,130 USD/ct × 2.5 ct
= 120,325 USD
* Note: This is the maximum opening price reported for the specified quarter
Example 2: Sapphire Price Evaluation
We want to find the price of an Oval Sapphire, 3.2 carats, Vivid Blue (no purple tint), Sri Lanka origin, Heat (treated), in Q4 2025.
Step 1: Select the table: "Sri Lanka: (1.00-20.00 CT): Q4 2025".
Step 2: Find the reference price per carat.:
For a 3.2 ct Sapphire, look at the 3.00-4.99 ct range. Since it is treated, select the "Heat" column. For a Vivid Blue color, select the "Vivid Blue" row. The resulting reference price is 3,880 USD/ct
Step 3: Calculate the value by substituting the numbers into the formula
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Price per Carat
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Sapphire’s Weight in Carats
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Exchange Rate (Currency) / USD – If currency conversion is not required, please leave this field blank.
= 3,880 USD/ct × 3.2 ct
= 12,416 USD
* Note: This is the maximum opening price reported for the specified quarter
Reference & Standards
Reference Criteria: The prices shown represent the maximum price for top-quality gemstones that meet these six highest criteria:
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Color
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Clarity: Eye clean
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Cutting: Good cutting
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Shape: Oval shape
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Origin
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Treatment: Heating
Color Grading Standard & Trade Terms:
Color grading follows the Chinese National Standard, which varies by gemstone type:
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Ruby: GB/T 32863-2016 "Ruby Grading"
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Sapphire: GB/T 32862-2016 "Sapphire Grading"
The report also provides clear definitions for key Trade Color Terms:
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"Pigeon Blood Red": The trade term for "Vivid Red" Ruby.
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"Royal Blue": The trade term for "Vivid Blue" or "Intense Blue" Sapphire that lacks a purple tint.
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"Cornflower Blue": The trade term for "Vivid Blue" or "Intense Blue" Sapphire with a slight purple tint.
Application for Industry Stakeholders
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For Entrepreneurs and Traders: Use it to evaluate inventory value and as a credible benchmark for business negotiations with domestic and international partners.
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For International Buyers and Investors: Acts as a tool to verify price reasonableness, helping to make confident investment decisions and reinforcing Thailand's potential as a standardized and transparent Jewelry Hub.
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For Gemologists and Enthusiasts: Serves as an in-depth resource to study the relationship between various factors (the 4Cs, origin, treatment) that affect gemstone valuation in the global market.
