Rainbow Lattice Feldspar: A Phenomenal New Gem

What is Rainbow Lattice?

Rainbow lattice feldspar is a rare and unusual gemstone that is found only in one place in the world.
This phenomenal gem is filled with gorgeous iridescent inclusions that look like confetti! Rainbow lattice feldspar is doubly phenomenal, containing hematite crystals that give it aventurescence and magnetite crystals that give it a rainbow lattice effect.

Rainbow Lattice Sunstone is a unique variety of Orthoclase Feldspar with its basket-weave pattern of iridescent Hematite and Magnetite platelet crystals is only found in Mud Banks, the Harts ranges, Northern Territories, Australia.

Rainbow Lattice Feldspar: A Phenomenal New Gem

Rainbow Lattice Sunstone

Where is Rainbow Lattice found?

There is only one place on Earth where it is found — the tiny Utnerrengatye mine in Harts Range, Northern Territory, Australia. Rainbow lattice feldspar was discovered there in 1985 and acknowledged as a new gem material in 1989. Rainbow lattice sunstone is produced from a remote part of the Australian desert known as the Mud Tank Zircon Field. It is an area consisting of dry plains with rocky outcrops that lies in the Harts Range north-east of Alice Springs, Northern Territory, Australia.

How rare is Rainbow Lattice?

Rainbow lattice is extremely rare. The only known source of this gemstone is the small mining claim in the Harts Range. The supply of Rainbow lattice is limited, and the stones are highly sought-after by collectors and jewelers.

Rainbow Lattice Sunstone from Mud Tank, Northern Territory, Australia.

What are the properties of Rainbow Lattice?

Rainbow lattice is a hard gemstone, with a Mohs hardness of 6.5 to 7. It is also a relatively dense gemstone, with a specific gravity of 2.55 to 2.65. Rainbow lattice is typically colorless or pale yellow, but it can also be found in shades of pink, orange, and green. The iridescence lattice pattern can be seen in all colors of Rainbow lattice, but it is most pronounced in the colorless and pale yellow stones.

Rainbow lattice sunstone is a feldspar comprised of 75 percent orthoclase and 25 percent albite.

Rainbow Lattice Sunstone from Mud Tank, Northern Territory, Australia.
Credit: Geologic Gallery | Boutique

Rainbow lattice sunstone is a type of orthoclase feldspar that exhibits a rare combination of aventurescence, adularescence, and a distinctive iridescence lattice pattern. The iridescence lattice pattern consists of inclusions that are the result of crystallographically oriented exsolution crystals within the feldspar crystal. Sunstone refers to its physical appearance instead of its chemical composition.

Sunstone inclusions may be composed of hematite, ilmenite, magnetite, native copper or goethite. The appearance of the aventurescence phenomenon depends on the size of the inclusions. Small particles produce a reddish or golden sheen, while larger inclusions create an attractive, glittery appearance.

It originally was believed that the black blades and triangle inclusions were ilmenite, but improved technology over the last three decades has shown them to be magnetite.

It was found that the host mineral is orthoclase, as previously reported in the literature and the inclusions causing the aventurescence are hematite. This research also discovered that the lattice patterns consist of orangey brown platelets of hematite and the black platelets consist of magnetite.

How is Rainbow Lattice Used?

Rainbow lattice is often used in jewelry, but it can also be used in other applications, such as cabochons and sculptures. The unique iridescence lattice pattern of rainbow lattice makes it a very attractive gemstone for jewelry.