EARNINGS PER COMMON SHARE: (Tables)

3 Months Ended

Mar. 31, 2013

EARNINGS PER COMMON SHARE:

Schedule of computation of basic and diluted earnings per common share

	Three months ended
	March 31,
($ in millions, except per share amounts; shares in thousands)	2013		2012
EPS Numerator:
Net income attributable to Rockwood Holdings, Inc. shareholders	$	18.9	$	75.8
EPS Denominator:
Basic weighted average number of common shares outstanding	78,530		77,384
Effect of dilutive stock options and other incentives	1,558		2,931
Diluted weighted average number of common shares outstanding and common stock equivalents	80,088		80,315
Basic earnings per common share attributable to Rockwood Holdings, Inc. shareholders:	$	0.24	$	0.98
Diluted earnings per common share attributable to Rockwood Holdings, Inc. shareholders:	$	0.24	$	0.94