Tannins and human health: a review. Chung KT, Wong TY, Wei CI, Huang YW, Lin Y. Department of Microbiology and Molecular Cell Sciences, University of Memphis, TN 38152, USA. Tannins (commonly referred to as tannic acid) are water-soluble polyphenols that are present in many plant foods.
How to Cast Jewelry. Jewelry casting is a process of making jewelry pieces that involves the pouring of liquid metal alloy into a mold. It is usually referred to as lost-wax casting because the casting mold is created using a wax model that is melted away to leave a hollow chamber in the middle of the mold.
What do those barely discernible numbers inside a ring or on the back of a charm mean? The value of jewelry made from precious metals is determined by the purity of the gold, silver, or platinum it contains. The number found on jewelry is a karat hallmark and tells you how much of a metal is in that piece. A hallmark is an indication of a piece of jewelryâs precious metal content. The karat stamp has been used in European countries since the 14th century.