70- 蓝宝石
P1 - The eerie phosphorescence displayed by a rare form of blue diamond can be used to identify individual gemstones and to distinguish natural blue diamonds from synthetic ones.
P2 - Phosphorescence process
SEM introduced the process.
The Hope Diamond example
P3 - The Hope Diamond has received little scientific attention.
EM and her colleagues studied the Hope Diamond, the Aurora Heart Collection, the Blue Heart Diamond and the blue diamonds in the Aurora Butterfly collection.
They shone a high-intensity UV light on each gemstone for 20seconds and measured its phosphorescence at various wavelengths.
P4 - The test showed that all natural type IIb diamonds glow for several seconds at 2 visible wave lengths - a blue and a reddish one
Differences in the peak intensities of those emmisions and the rates at which they wane provide a virtual fingerprint for each stone.
P5 - Neither the synthetic stones nor the color-enhanced gray gemstone glowed at the 660-nm wavelength.
Could be used to distinguish between artificial diamonds and the true blue gems.
=> solve one of the big problem in diamond markets
P6 - Phosphorescence from one part of a large gem to another are almost the same
=> if a large diamond were stolen and cut into smaller stones, scientists would still be able to identify
1. The P can distinguish natural blue diamonds from synthetic ones in cheap and easy way
2. In blue diamond, P phenomenon is normal via slowly releasing a substance in the dark. After exposure to light, these diamonds will shine in different color from blue to fiery red. For an 45.52 carat diamond, the light can remain as long as a minute.
3. Describing an opportunity to do further research on various diamond under 20 seconds ultraviolet light.
4. Reddish P is rare in diamond. The two wavelengths decide the final glow.
Neither the synthetic stones nor the color enhanced gray stone glowed at the 660nm wavelength. The rationale has been used to idenfication
• Pho-: distinguish natural blue diamonds from synthetic ones
• Process: energy previouly absorbed→ release
○ Blue diamond
§ exposure to light
§ Glow in colors
□ e.g. 45.53-carat Hope diamond: orange-red glow
• 2005 Aurora Heart collection : on loan
○ Researchers:
§ 67natural, 3 systhetic and a gray one
§ Shone ultraviolet light
§ Measure the pho-
□ All natural : glow at 2 wavelengths
® 500-nm
® 660-nm
□ Provide Fingerprint
® synthectic & gray stone:No 660-nm
® Solve big problem
◊ Distinguish the artifiacl ones
◊ Identify the stolen or smaller stones