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To: Ilaine who wrote (31150)	7/7/1999 4:50:00 PM
From: PCModem	Read Replies (1) \| Respond to of 71178

"...why is lapis lazuli about the same color as cobalt blue, but without cobalt? " Maybe you need to adjust the brightness and/or contrast on your monitor. On mine they are quite different. That or you just can't see the difference... PCM

To: Ilaine who wrote (31150)	7/7/1999 5:00:00 PM
From: Jacques Chitte	Read Replies (1) \| Respond to of 71178

galleries.com This is a bit on the mineral lazurite. It doesn't seem to contain a colorigenic impurity - indeed by the formula it should be white. Maybe there is something about its structure on a scale larger than ordinary crystal features that imparts the color. A typical mineral or glass is colored because of color absorption by included transition metal ions. There are exceptions - like the blood-red of colloidal gold. Lapis seems to be one of the unusual ones. The samples of lapis shown in your jpeg links come up pretty dark on my screen - royal tending to midnight blue.