Onyx Black Agate

✨Black agate is mainly composed of SiO2 (silica). When it is very pure, it appears gray. However, when it contains various pigment ions, it can exhibit colors such as red, black, blue, green, etc., with deep or shallow banding structures. These bands can come in different colors (red, blue, purple, green, black, white, etc.). If they appear as black and white stripes, they are called striped black agate. Those with red and white stripes are known as wrapped black agate. If the black bands in the striped black agate are wide, they can be cut out separately and processed into black agate beads. It is inevitable that there may still be very fine white bands visible under sunlight. Therefore, it is normal to see fine white stripes in black agate beads.

🔮Black agate generally ranges from transparent to opaque, with a hardness of 7, a glassy luster, and a conchoidal fracture. Its most prominent artistic feature is its beautiful patterns in various forms, such as concentric bands, layered patterns, ripples, wrapped threads, and grass-like branches, with a wide range of colors including white, gray, yellowish-brown, and black. Because black agate has natural pores, it can also be dyed in various colors such as red, blue, green, yellow, brownish-purple, etc. In Brazil, dyed black agate is called "umbu."

🔮Most black agates in the market are color-enhanced, but since no other substances are added during the enhancement process, they are still considered natural gemstones in jewelry appraisal. This type of agate has a deep black color and can easily be confused with other black gemstones, so caution should be taken when purchasing.