Gelin Abaci is a company that grew out of a concept held by Gabriel Gelin and Sam Abaci. Together they have a combined total of more than 50 years in the jewelry industry.GelinAbaci’s contemporary tension set diamond engagement rings are on sale at Family & Co. Jewelers at half price! The Stone Floats In Mid-Air In These Tension Settings! There is approximately 65 to 95 pounds applied to a stone which is greater than a typical four or six prong setting. The Center Diamond Is Sold Separately. Setting The Diamond And Sizing To Fit Her Finger Is Included In The Sale Price. Sale Price Applies To In-Stock Rings Only; Not To Any Special Orders.