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 from Mahidol University International College with a BA in biological science. She taught science at a high school academy for a number of years. She also earned the GIA Graduate Gemologist diploma in 2017. Thasanee joined GIA as an on-campus instructor in 2018. She teaches Graduate Colored Stones and the Graduate Diamonds, and uses her educational attainments to expand her knowledge of gemology constantly. Thasanee views gemology as a unique blend of beauty and science, is passionate about teaching, and loves sharing her enthusiasm for gemology with her students.

Pitchaya Lopiti

Pitchaya graduated with a degree in material science (gemology) from Srinakharinwirot University in Thailand. Her studies included gemology, jewelry making and production, jewelry design, illustration, and CAD/CAM. After graduation, she was a sales executive and customer service representative for Malca-Amit Co., Ltd, a transport company for precious goods. She also worked in sales for an upscale jewelry company. Pitchaya is now an instructor at GIA in Bangkok, where she teaches the Diamond Grading, Colored Stone Grading, and Gem Identification lab classes, as well as the Accredited Jeweler Professional and Graduate Colored Stones diploma programs. Pitchaya's background in material science and gemology, along with her work in the jewelry industry make her a valued resource for her students. She particularly enjoys sharing ideas and engaging in conversations with them.

Panissara Navasamakkarn

Panissara earned her bachelor's degree in science (geology) from Chulalongkorn University. Her studies included gemology, mineral deposit, and geotectonics. After she graduated, she worked as a diamond grader for GIA in Bangkok. She excelled at this precise and demanding work and was hired as an instructor, where she now leverages her college education and lab experience. Panissara aspires to help her students excel in their studies so they can have successful careers.

Piyapratch Poonsilp

Piyapratch graduated with a bachelor’s degree in biology from Chiang Mai University and with a master’s of science in chemical biology from Chulabhorn Graduate Institute. He then taught science and chemistry 2006 at high school and undergraduate levels. After earning his Graduate Gemologist diploma, Piyapratch joined GIA in Thailand in 2015 as an on-campus instructor. With his education background and teaching experience, Piyapratch is an excellent resource for students seeking gemological and scientific knowledge. His dedication and efforts ensure GIA students can accomplish their goals and succeed in their career.

jewelry manufacturing arts

Ninnate Plumkratoke

Ninnate graduated with a bachelor's degree in material science (gemology) from Srinakharinwirot University. Her studies included gem identification, jewelry design, jewelry making, and marketing. Ninnate also received a master’s degree in contemporary jewelry design from Silpakorn University, Thailand. During her studies, she worked as a part-time jewelry designer for a company that exported pieces to the Middle East. After graduation, Ninnate worked as a freelance jewelry designer for a jewelry company and in marketing and design for a diamond manufacturer. She teaches the Jewelry Design and Quick Design courses at GIA in Thailand. Her goal is to inspire students to create their own style. Ninnate loves working closely with her students and sharing perspectives on design.