求问：如果是网购钻石，怎么避免出现奶油钻，咖啡钻？

请问大家，GIA证书 1克拉的L色 SI VG 值得购买吗？
Round Brilliant
Measurements: 6.46 - 6.52 x 3.94 mm
Carat Weight: 1.01 carat
Color Grade: L, Faint Brown
Clarity Grade: SI2
Cut Grade: Very Good
Proportions
Depth: 60.7%
Table: 61%
Crown Angle: 33.5°
Crown Height: 13.0%
Pavilion Angle: 41.6°
Pavilion Depth: 44.5%
Star Length: 50%
Lower Half: 80%
Girdle: Very Thin to Slightly Thick (4.0%)
Culet: None
Finish
Polish: Very Good
Symmetry: Good
Fluorescence: None

在论坛里面找蒂，比如这颗就是咖钻，颜色后面加了