manjak
/ˈmandʒak/(also manjack) Now chiefly Geology
noun
A lustrous black variety of asphaltite which occurs on Barbados and Trinidad and was formerly used as a fuel and in the manufacture of lacquers.
Origin
Mid 17th century; earliest use found in Richard Ligon (c1585–1662), business agent and natural science writer. Origin uncertain. Perhaps ultimately from Arawak. The first element has probably been influenced by mount and man; the form with mun- in quots. 1683, 1699 is less readily accounted for, and may therefore be closer to the original. With the second element, compare black jack.