Gold dust? That's a nice twist on the usual scam. But this is most definitely a scam. Don't reply to messages like this; you should delete them instead.
This is a rare case, by the way, when you're not asked to reply to a different email address. That's the sign of a hacked mailbox, or a mailbox set up specifically by the scammer.
From: tony kess firstname.lastname@example.org
Subject: WITH TRUST
Date: December 18, 2011 6:21:12 PM PST
I am Tony Kess from London 31 year of age I have a little problem my late friend who die two days ago had 200 kilo of Gold Dust with a Gold Mining Company in Malaysia, I am contacting you because i need your help in regards to this issue, I have contacted the Gold Company in Malaysia to ship the 200 kilo of Gold Dust to me and the Company ask me to pay for the shipment of the Gold Dust, I am contacting you and at the same time if you can be my partner so we can both put head together and pay the shipping cost and share the Gold Dust among our self 50/50, Please note if you want the Gold Company to ship in the Gold Dust to your destination first no problem I believe that when the Gold Dust finally get to your destination later i can fly down and meet with you and collect my own share of 100 kilo.
What i needed from you is trust and honesty once I confirm your return email in agreement to my email I shall send you the contact details of the Gold Dust Company in Malaysia so you can contact them yourself.
I await to hear from you.