GIA Certified

We exclusively propose diamonds certified by the GIA, the one and only grading authority for the diamond trade worldwide. Other laboratories over-grade stones, giving you a false sense of quality and value.

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100% Custom

The perfect engagement ring does not already exist in a display. It should be custom made with you, for you. Our onsite expert craftsmen will make that dream a reality.

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Friendly Support

At our studio, you will be treated in a private setting with all the focus on the making of your diamond purchase experience the most personal, relaxing, and educational diamond buying experience.

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Personalized Service

Our best engagement rings are created with a personalized service. The service begins with a consultation with Sevan, who will learn more about you and your inspiration, helping you to develop your ideas and final vision.

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A Brief History…

design by sevan


Sevan Tosun was born in 1977 in Istanbul, Turkey, the former capital of the Byzantine and Ottoman Empires, and home to one of the world’s finest jewelry merchants. At the age of 10, Sevan carried on his father’s legacy and began a full-time apprenticeship with one of the most respected jewelry houses in Istanbul. By age 16, he had learned every facet of the trade, cultivating the highest level of skills a jeweler could achieve in metal, diamond setting, and design, imagining intricate designs and creating pieces from start to finish.

With a fantastic array of skills and dreams of a better life, Sevan left his roots in Istanbul as a teenager and headed for Canada with just $250 in his pocket. Connecting with a relative who had already emigrated to Canada, Sevan arrived in Toronto. Within a few years, Sevan developed a reputation as the most excellent jeweler in the area. In 2000, he founded A.S.T.Jewelry. Today, Design by Sevan stands as one of the premier custom diamond engagement ring boutiques in the Fashion District, Toronto.

Custom engagement ring design awards


For many jewellers, making jewellery is a profession – for Sevan, it is an identity.

Discuss visions,ideas and most importantly educate you on diamonds and the whole process.It’s not about a sale or about me it’s about the relationships and trust. Make an enquiry with us today.

Custom Diamond Engagement Rings in Toronto

NO SALES PRESSURE SHOWROOM – No unwanted sales pressure. I promise!

  • Every client that walks in has already done their “google” research but there is so much more than what lies in the internet to know about diamonds. It seems so simple but every client leaves my office with a new prospective; something you can’t learn online.
  • O It’s not about a sale or about me it’s about the relationships and trust I build with my clients that make my each engagement ring I create unique. Most importantly I want everyone that puts on a engagement ring from Design by Sevan to love it and leave happy .
  • We are fully equipped to handle all of your engagement ring shopping needs. This is what you get. My expertise, my education and my honesty. we are forward to meeting you.
Things to Keep in Mind While Buying diamond jewellery

We specialize in designing custom diamond engagement rings in Toronto and the surrounding areas. Already have an idea for a diamond engagement ring or another piece of jewelry? Let us help you bring your idea to life, offer the best design advice, and create your one of a kind piece. We design all of our engagement rings in-house, and each ring is created with the same amount of intricate detail, care, and professionalism. Our engagement rings are individually made for each client.

Questions? Ask us anything.