The crater is approximately 24m in diameter, and it is the only known crater formed by a mesosiderite.  Local rock exhumed by the crater was studied isotopically and found to have been exposed on the surface for approximately 270,000 years.¹ It is one of the smallest known true simple fragmentation craters known in the world, and it has recently come under more study because of its possible use as an analogue to impact craters on Mars that have undergone slow erosion over relatively long periods of time.²  Thanks to the climate of the region for the past several hundred thousand years, this small crater has been well preserved.  It should be noted that the mesosiderites found around the crater have a terrestrial age matching that of the crater, and they have one of the highest non-Antarctic Earth-residency times of any meteorites.  A few Omani Lunars have terrestrial ages in the millions of years, but a terrestrial age of 270,000 years is very uncommon. 

Update as of 12/2013: A recent study has been published clarifying the age of the crater and some other information.  Here's a link: The Discovery and History of the Dalgaranga Meteorite Crater, Western Australia.  As it turns out, the age of the crater is poorly defined and could be as low as ~25,000 years (there are a few lower estimates, but those seem doubtful).  The article also suggests that less than ~30 kilograms of material has been recovered and curated, with specimens being nearly impossible to find since the 1950's.  And it contains a wealth of other information worth reading if you're curious about the meteorite and its enigmatic crater.