Gemstones of Aaron's Breastplate and the Urim & Thummim is a booklet with 43 pages with many images. This booklet explains what gemstones were on Aaron's Breastplate and the Urim & Thummim and how it was used. See Table of Contents. Many of the gemstones on the breastplate have been mistranslated. For example, the word translated "sapphire" does not refer to the blue sapphire we know today. This is a great booklet if you want to know more about the gemstones of Aaron's Breastplate and the Urim & Thummim. The gemstones of Aaron's Breastplate are not the same as the twelve foundation stones of New Jerusalem.