This transparent quartz has colors of both amethyst and citrine, and is called ametrine or amethyst-citrine.
AMETRINE isn’t a birthstone.
Chemical composition: SiO2
Color: Bicolor orange/yellow and purple
Refractive index: 1.544 to 1.553
Specific gravity: 2.66 (+0.03/-0.02)
Mohs hardness: 7
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