In many cases, if the truth were known, Howlite would be better known as a Turquoise immitation. Howlite is frequently (and very convincingly) dyed blue to pass as Turquoise. It even contains gray to black threadlike impurities resembling the veining in Turquoise.
A current source of crystals is Cape Breton Island, Victoria County, Nova Scotia, Canada although these crystals are not suitable for faceting. The massive type can be found at the Sterling Borax Mine, Tick Canyon, Lang, Los Angeles County, California, USA (and a few other California locations); Magdalena, Sonora, Mexico; Susurluk, Turkey; Baljevac na Ibru, near Kraljevo, and near Bela Stena, Yugoslavia.