Complex sentence: Made of high gem quality, flawless diamonds, usually with 16 facets, they typically weigh 1/8 to 1/3 carat (25 to 70 mg).
Split into simpler sentences: Made of high gem quality, flawless diamonds, usually with 16 facets. They typically weigh 1/8 to 1/3 carat (25 to 70 mg).