Makatite Locality: Aris Quarries (Ariskop Quarry; Railway Quarry), Aris , Windhoek , Windhoek District, Khomas Region , Namibia ( Locality at mindat.org ) Size: 7.5 cm x 3.9 cm x 1.7 cm A very fine 1.6-cm spray of acicular crystals of the rare species Makatite, from finds that started trickling out in the mid 1990s. Still fairly rare, even today, from this unusual phonolite deposit. Ex. Al Ordway Collection. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Makatite
Makatite is an IMA-recognized mineral species in the silicate class, with the chemical formula Na₂Si₄O₈(OH)₂·4H₂O.
It crystallizes in the monoclinic crystal system (space group P2_1/c).
Key properties: specific gravity 1.97–2.07; optically biaxial.
IMA symbol Mkt, IMA status: approved, named in 1969.
Found in cores from drill holes in a lacustrine evaporite series (Lake Magadi, Kenya); leached from natrosilite in an alkalic pegmatite in a differentiated alkalic massif (Lovozero massif, Russia).
It is found associated with Trona, erionite, magadiite, anorthoclase, gaylussite, organic material (Lake Magadi, Kenya); natrolite (Lovozero massif, Russia); vuonnemite, sodalite.
The name comes from the Masai word emakut, meaning soda, in allusion to the high sodium content of the mineral.