GIA instructors are passionate educators who bring years of industry experience to the classroom. All are leaders in their fields, and all are dedicated to helping you gain knowledge, acquire skills and launch your career.


Thasanee Khanijou

Thasanee graduated with a Bachelor of Science in Biological Sciences from Mahidol University International College (MUIC). She has earned the GIA Graduate Gemologist® diploma (GG) and the Applied Jewelry Professional diploma (AJP®). Thasanee joined GIA as an instructor in 2017 and teaches the gemology program. Her bachelor of science degree and strong scientific background have given her a well-rounded skill set to constantly expand her knowledge of gemology. Teaching in a high school academy for some years being an instructor comes naturally for Thassanee. She believes that gemology is an integration of both her interests, beauty and science. Her range of scientific experiences along with her passion for teaching has made her a compassionate and enthusiastic instructor at GIA.

Pitchaya Lopiti

Pitchaya graduated with a Bachelor’s degree in Material Science specializing in gemology from Srinakharinwirot University in Thailand. Pitchaya joined GIA in Thailand in 2011. She has earned the GIA Graduate Gemologist® diploma (GG), Graduate Pearls diploma(GP), and Applied Jewelry Professional (AJP®). In her role as an instructor, she has been teaching the entire range of GIA gemology programs and has given numerous trade seminars both domestic and international. She previously worked in international logistics and jewelry companies which have provided her broad experience in all industry aspects as well as in gemstone identification. In 2016, Pitchaya received the prestigious GIA Staff of the Year Award for her outstanding contributions. She became Manager of Instruction at GIA in Thailand in 2018. Her solid background in gemology, along with her expertise in gemology makes her a valuable source of information for her students enabling them to achieve their goals and succeed in their careers.

Panissara Navasamakkarn

Panissara graduated from Chulalongkorn University with a Bachelor’s degree in Science (geology). Her studies included gemology, mineralogy and geotectonics. In 2012, Panissara joined GIA laboratory as a diamond grader gaining expertise and attention to detail in diamond grading. She joined the gemology instructor team in 2014. She has earned the Graduate Gemologist® diploma (GG), Graduate Pearls diploma (GP), Quick Design and Applied Jewelry Professional diploma (AJP®). Panissara’s background in geology, gemology and diamond grading provided a solid foundation as a gemology instructor. She would like to support her students in their studies to successfully develop their careers.

jewelry manufacturing arts

Ninnate Plumkratoke

Ninnate received a Master’s degree in Contemporary Jewelry Design from Silpakorn University in Thailand. She also graduated with a Bachelor’s degree in Material Science specializing in gemology. Her studies included gem identification, jewelry design, jewelry manufacturing arts, and marketing. During her studies, she worked as a jewelry designer for an international jewelry company. After graduation, Ninnate worked as a freelance jewelry designer for a jewelry company and held a marketing and design role for a diamond manufacturer. She has earned the GIA Graduate Gemologist® diploma (GG), Graduate Pearls diploma (GP), Jewelry Design program (JD) and Applied Jewelry Professional diploma (AJP®). Ninnate loves working closely with her students and encourages them to create their own style and share their design perspectives.