OPALS CAN BE UNLUCKY
MELBOURNE (By Airmail)—Whether the old superstition that opals, as gems, are unlucky still holds good or not may be doubtful, but scientists have discovered that opal, if inadvertently mixed in concrete is definitely unlucky! The Council for Scientific and Industrial Research, in Melbourne, has i completed a five-year programme of tests with samples of sand, gravel and rock from all states of Australia, and j 16 kinds of cement. The tests were inspired by reports from the United States, where crack- 1 ing in concrete structures was found i to be caused by a reaction between | cement and certain kinds of gravel, all j of which contained opal. j Australia’s CSIR research team con-j firmed the American discovery. ■ Tests showed that when opal is present in concrete, particles gradually soften and swell, expanding and cracking the cement. Opal occurs extensively in Australia, but only a few varieties have any value as gem-stones.—NZPA-Reuters.)
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https://paperspast.natlib.govt.nz/newspapers/NA19481222.2.46
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Northern Advocate, 22 December 1948, Page 6
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156OPALS CAN BE UNLUCKY Northern Advocate, 22 December 1948, Page 6
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