Gemological Science International (GSI) has made a new addition to its senior leadership team as it looks to progress its business development.

Diamond and jewellery certification specialist GSI has tapped Jonathan Tack as its new executive vice president of business development.

“I am thrilled to welcome Jonathan Tack to GSI,” said Debbie Azar, president and co-founder of GSI. “Our team is made up of leaders from the diamond and jewellery industry, and I am confident that Jonathan’s enthusiasm, energy, and vast industry knowledge will help GSI achieve continued growth and success.”


Jonathan has over 25 years of experience in the luxury goods sector. Following a decade of service as vice president of sales for Suberi Brothers, where he revamped the legacy brand and launched e-commerce, Tack then founded Proposition Love where he designed for Cher, Kathy Griffin and Tori Spelling and even appeared on the Chelsea Handler Show.

“I am delighted to join such an esteemed and prestigious global organisation,” said Jonathan Tack, new executive vice president of business development, GSI. “The GSI team is building consumer trust and confidence in our industry through its integrity and innovation.

“I look forward to creating new opportunities that will be beneficial for GSI and for the entire diamond and fine jewellery industry.”

GSI is a globally renowned gemmological organisation that offers services to the diamond and jewellery industry, including grading reports and services for diamonds (both natural and lab-grown), colored gemstones, and jewellery.