corundum, ruby, Vietnam.12, inclusions.5, gems

Reports on rubies from northern Vietnam, believed at the time to originate in Hoang Lien Son Province, about 250 km northwest of Hanoi. Rough crystals range from pale to strong red, sometimes with a distinct violet component, and show weak red to yellowish-red pleochroism. The authors describe their standard gemological properties, absorption characteristics and internal features, comparing the material with rubies from other deposits. The study was among the earliest gemological reports on the newly important Vietnamese ruby occurrences, whose material could closely resemble ruby from Myanmar.