Hydrogen and air mixtures, within the flammable range, can explode and may burn with a pale blue, almost invisible flame.

在可燃范围内的氢和空气的混合物可能爆炸，也可能燃烧，火焰是淡蓝色，几乎看不见。

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Items of "Blue Rarity" or higher no longer burn up in lava.

蓝色珍品道具和更高等级的道具不再会被岩浆烧掉。

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It will burn with a pale blue, almost invisible flame.

氢燃烧时火焰是淡蓝色，几乎不可见。

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While some gems may appear colorless in daylight, under ultraviolet light they can burn a bright blue or green.

FORBES: Cindy Chao's Butterfly Brooch Added to Smithsonian Gem Hall