Blue Purple Terra Agate 14x40mm Rice 15-16 Inch 5PF Citrine is a transparent Quartz

Citrine is a transparent Quartz

but those varieties are transparent

olive green and gray-green

and much of the black Onyx on the market has been artificially colored

Tourmaline has often been confused with other stones

Blue Purple Terra Agate 14x40mm Rice 15-16 Inch 5PF Citrine is a transparent QuartzWith the possible exception of the horizon meeting the bright blue sky on a perfect summer day, or a sandy beach blending into a tropical bay, there may not be a beautiful blue and brown combination than that of Terra Agate. The rounds even resemble little Earths, the brown spaces creating new continents aside the unfamiliar oceans. A form of chalcedony made of quartz, Terra Agate contains the best of nature in a variety of small shapes.