Howlite, a calcium borosilicate hydroxide (Ca2B5SIO9(OH)5), is a borate mineral found in evaporite deposits. Howlite was discovered near Windsor Nova Scotia in 1868 by Henry How (1828–1879), a Canadian chemist, geologist, and mineralogist.
How was alerted to the unknown mineral by miners in a gypsum quarry,
who found it to be a nuisance. He called the new mineral
silico-boro-calcite; it was given the name howlite by James Dwight Dana shortly thereafter.
The most common form of howlite is irregular nodules, sometimes
resembling cauliflower. Crystals of howlite are rare, having been found
in only a couple localities worldwide. Crystals were first reported from
Tick Canyon, California, and later at Iona, Nova Scotia. Crystals reach a maximum size of about 1 cm. The nodules are white with fine grey or black veins in an erratic, often web-like pattern, opaque with a sub-vitreous lustre. The crystals at Iona are colorless, white or brown and are often translucent or transparent.Howlite is commonly used to make decorative objects such as small
carvings or jewelry components. Because of its porous texture, howlite
can be easily dyed to imitate other minerals, especially Turquoise because of the superficial similarity of the veining patterns. The dyed howlite (or magnesite) is marketed as turquenite.
Howlite is also sold in its natural state, sometimes under the
misleading trade names of "white turquoise" or "white buffalo
turquoise," or the derived name "white buffalo stone."