(IDEX Online) - US jeweler Helzberg is expanding its own-brand offering, with a new range of a dozen lab-grown diamond engagement rings.It's been selling other brands of bridal and other lab-grown jewelry since 2017.But it has now partnered with Jenny Packham, a favorite designer of the British Royal Family, who has created a dozen platinum rings with colorless lab-grown diamonds.Helzberg says it is the "first colorless lab-grown collection in the industry.Items range from a 1/3-ctw wedding band at $699.99 to an engagement ring with an oval 1-ct center stone plus a halo (2-ctw) for $5,999 (pictured).Helzberg Diamonds has 170 stores in the US and is a subsidiary of Berkshire Hathaway.