White Howlite and Magnesite
There are no two stone types so ambiguous to the jewelry designer as Howlite and Magnesite, both interesting and decorative white gemstones. Stones sold as Howlite, may actually be Magnesite. And stones sold as Magnesite, may be Howlite.The major reason for the confusion is that these naturally white and creamy white stones look remarkably alike. In addition to color, both stones can form as irregular nodules that often appear in the shape of a cauliflower head with a simple or complex web-like matrix running through the nodules—natural features that Miriam uses to bring an edgy look to her Howlite and Magnesite jewelry designs. It is only with chemical testing and microscopic evaluations by a gemologist that the differences between the two stone types can be determined. Below are some of the facts we know about these beautiful white stones.
- Howlite is a calcium borosilicate formed by the combination of boric acid and silicon dioxide with calcium in gypsum sediments.The natural stone is opaque and has the appearance of milky white marble or porcelain with a matrix of light gray, or light to heavy black or dark brown matrix running through it in spider web-type veins. Deposits of natural tan opaque Howlite have also been found. Howlite that is matrix-free and pure white is rare. Even more rare are transparent and translucent Howlite crystals that are colorless, white, or brown—first unearthed from Tick Canyon in the Sierra Pelona Mountains of California, and later at Iona, Nova Scotia. Howlite is named for Canadian mineralogist Henry How, who discovered it near Windsor, Nova Scotia in 1868. Most stones now come from California and Los Angeles, but deposits have also been found in Turkey, Germany, Mexico and Russia.
- Magnesite is a soft magnesium carbonate mineral. While it is generally a creamy white, it also appears naturally as yellow, brown, or gray. Like Howlite, it has a porcelain-like appearance. Its masses occur within a light or dark host rock matrix, giving it a webbed, mottled, or streaked appearance. Like Howlite, it may also appear in cauliflower-like clumps. Magnesite is found in many countries in Europe and Africa, and in Brazil, China, Korea—as well as in the United States.
- Because Howlite and Magnesite are relatively “soft” stones, they are often dyed to mimic Turquoise, Lapis, and Red Coral. Miriam always asks about treatment when she purchases her stones, and does not knowingly buy or use dyed stones. She values the natural white, creamy white, and porcelain-like qualities of Howlite and Magnesite—and the web-like patterns running through the stone nodules. She does her best to distinguish between the two stones based on the colortone and web patterns—and information from the source.