religious ring 3D 打印模型

描述

the weight of this men's ring with 18 carat yellow gold is 17 grams and 95 whistles
and with 18 carat white gold, 17 grams and 8 whistles
and with 925 silver, it weighs 12 grams and 7 whistles.
history of silver
silver's history is long. the first evidence of silver mining dates back to 3000 b.c., in turkey and greece, according to the rsc. ancient people even figured out how to refine silver. they heated the silver ore and blew air over it, a process called cupellation. the silver does not react to the air, but the base metals such as lead and copper oxidize and separate from the precious metal.
silver forms in star explosions called supernovae, as does gold. a study published in september 2012 in the journal astronomy and astrophysics found that smaller stars that explodeproduce silver, while larger stars produce gold.

an 1804 silver dollar. (image credit: public domain)
silver really exploded on earth, however, when europeans landed on the new world in 1492. spanish conquerors discovered that south america was home to rich veins of silver and silver ore, and they mined that wealth enthusiastically; according to the silver institute, an industry trade group, 85 percent of the silver produced worldwide came from bolivia, peru and mexico between 1500 and 1800.
silver played a big role in making early photography possible. silver nitrate (silver combined with nitrogen and oxygen molecules) was used on photographic plates in the first, clunky cameras, according to the rsc, because it reacts to light by turning black — enabling photographers to capture an instant of light. even with the rise of digital cameras, silver remains part of the traditional photographic process. as of 2003, the most recent year data is available, 1,920 metric tons of silver each year went to use for photographic purposes. electrical and electronic uses were the second most-common single industrial use for silver, with 1,230 metric tons going into wires and gadgets in 2003. jewelry, sterling silver and silver electroplated objects ran a distant third, using only 486 metric tons. another 1,810 metric tons went to various other uses.