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 gemmology programme. Her bachelor of science degree and strong scientific background have given her a well-rounded skill set, enabling her to constantly expand her knowledge of gemmology. Having taught in a secondary academy for several years, being an instructor comes naturally to Thassanee. She believes that gemmology 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 specialising in gemmology 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 taught the entire range of GIA gemmology programmes and has given numerous trade seminars, both domestically and internationally. She has previously worked for international logistics and jewellery companies which has provided her with 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 gemmology, along with her expertise, 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 gemmology, mineralogy and geotectonics. In 2012, Panissara joined the GIA laboratory as a diamond grader, gaining expertise and attention to detail in diamond grading. She joined the gemmology instructor team in 2014. She has earned the Graduate Gemologist® diploma (GG), Graduate Pearls diploma (GP) and the Quick Design and Applied Jewelry Professional diploma (AJP®). Panissara’s background in geology, gemmology and diamond grading provided a solid foundation as a gemmology instructor. She would like to support her students in their studies to successfully develop their careers.

jewellery manufacturing arts

Ninnate Plumkratoke

Ninnate received a Master’s degree in Contemporary Jewellery Design from Silpakorn University in Thailand. She also graduated with a Bachelor’s degree in Material Science specialising in gemmology. Her studies included gem identification, jewellery design, jewellery manufacturing arts and marketing. During her studies, she worked as a jewellery designer for an international jewellery company. After graduation, Ninnate worked as a freelance jewellery designer for a jewellery 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 diploma (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.