Precious metal "precious" metal can also be determined by high demand or market value. Precious metals in bulk form are known as bullion and are traded on commodity markets. Bullion metals may be cast into ingots or minted into coins. The defining attribute of bullion is that it is valued by its mass and purity rather than by a face value as money. The level of purity varies from issue to issue. "Three nines" (99.9%) purity is common. The purest mass-produced bullion coins are in the Canadian Gold Maple Leaf series, which go up to 99.999% purity. A 100% pure bullion is
Aurum Geyser decreases and increases its interval at regular times during a week. Eruptions last about 90 seconds and range in height from to . An eruption is usually preceded by bubbling in two small vents nearby. On rare occasions, an eruption will be followed by a second smaller eruption 5 to 10 minutes after the primary eruption. Aurum Geyser Aurum Geyser is a geyser in the Upper Geyser Basin of Yellowstone National Park in the United States, on Geyser Hill. Aurum can, at times, be very predictable. Other times it can be very erratic. Observations have led to the theory that