Brown Band in Lab Grown is a Growth Remnant
November 05, 24
(IDEX Online) - Laboratory staff at GIA have identified an unusual dark brown band in a CVD lab grown diamond.
They say it looks graining in a natural diamond (a defect in the diamond's crystal structure) but is actually a "growth remnant" from CVD (Chemical Vapor Deposition) possibly caused by a "start-stop cycling growth process".
The single single dark brown band, about 2.2 mm long, was seen in a 3.14 carat F-color VVS2-clarity oval brilliant diamond submitted for grading in Surat, India.
In the latest edition of GIA's Lab Notes, authors Srushti Tanti and Raju Jain say the band was visible under the microscope as well as with a 10�- loupe.
They say the subtle banding is different from a cloud of graphite inclusions at a growth interface they've seen in another CVD diamond.
Photomicrograph by Raju Jain