Not a diamond; visual indicators (conchoidal fracture, bubble-like inclusions, deep blue color) suggest this is man-made cobalt-colored glass or slag, sometimes referred to as 'sea glass' or industrial cullet.
Not a diamond; visual indicators (conchoidal fracture, bubble-like inclusions, deep blue color) suggest this is man-made cobalt-colored glass or slag, sometimes referred to as 'sea glass' or industrial cullet. · Rough irregular shard / fragment
Uncut / Raw fragment Cut
Carat
Cannot be precisely determined visually without density testing, but visually estimated around 3.0 to 5.0 carats equivalent mass
Color
Deep vivid blue (Fancy Dark Blue in gemological terms, though material is glass)
Clarity
Included (contains trapped gas bubbles and localized imperfections typical of glass)
Shape
Rough irregular shard / fragment
Overall Assessment
The specimen shown is a piece of cobalt blue glass featuring classic diagnostic indicators such as conchoidal fractures and internal gas bubbles. It is neither a diamond nor a precious gemstone.
Cut Quality
Uncut / Raw fragment
Brilliance
Low due to lack of standard facet alignment and high internal absorption of deep blue color
Fire
None, glass lacks the high dispersion of diamond
Scintillation
Minimal, localized reflection from uneven surface planes
Proportions
N/A for raw unshaped material
Symmetry
Asymmetrical raw shard
Polish
Raw unpolished fractured surface
Fluorescence
Likely inert or faint depending on UV source, standard for cobalt glass
Inclusions
Rounded gas bubbles visible within the matrix, characteristic of manufactured glass rather than natural crystalline gems
Blemishes
Conchoidal fracture marks, chipping along edges, and surface wear
Origin
Man-made industrial or decorative glass waste
Treatment Detection
Material itself is a manufactured synthetic glass product
Estimated Value
Nominal decorative or craft value (under $10 USD)
Certification Estimate
Not eligible for certification by major gemological laboratories (GIA, AGS, IGI) as a gemstone
Investment Potential
None as an investment asset
Similar Diamonds
None, as this is completely unrelated to diamond
Setting Suggestions
Wire-wrapping or bezel setting if used for ornamental craft jewelry
Care & Maintenance
Standard cleaning with warm soapy water and a soft brush; avoid harsh impacts as glass is prone to chipping
Interesting Facts
Cobalt glass has been historically used to imitate fine blue sapphires or lapis lazuli in costume jewelry and decorative items