Question: What was Britain's (2013) birthstone when the U.S (2013) birthstone was ruby?
SQL: SELECT "Britain (2013)" FROM "2-17891889-1" WHERE "U.S. (2013)" = 'ruby';

Question: What was the U.S birthstone in 1912 when in 2013 the birthstone was amethyst?
SQL: SELECT "U.S. (1912)" FROM "2-17891889-1" WHERE "U.S. (2013)" = 'amethyst';

Question: What was the U.S birthstone in the 15th-20th century when in 2013 it was amethyst?
SQL: SELECT "15th- 20th century" FROM "2-17891889-1" WHERE "U.S. (2013)" = 'amethyst';

Question: Which month in 2013 did the U.S. use the ruby birthstone?
SQL: SELECT "Month" FROM "2-17891889-1" WHERE "U.S. (2013)" = 'ruby';

Question: In 1912 when the U.S used sapphire, what was the Hindu birthstone?
SQL: SELECT "Hindu" FROM "2-17891889-1" WHERE "U.S. (1912)" = 'sapphire';