Since silver peaked in April of this year, it has declined considerably from around $50 an ounce to $32 today. During the same period, gold has continued its consistent uptrend. Given this, it may seem like silver is a good relative value play right now. While it may be so, I think that platinum offers an even better value.
First of all, we can look at platinum's price relative to gold and silver historically. By using the ratio of platinum to other precious metals, we can see how the metals are trading relative to each other and to their historical ranges. Currently, the platinum to gold ratio is below one, an indication that platinum's price is lower than that of gold. This is quite rare as platinum's price usually stays above gold's price.
Platinum is also trading at a low level compared to silver, with its price only 50 times that of silver. For the last several months, it has traded near this level, but prior to this, the last time the ratio of 50 to 1 was seen was in 1985.
Another factor which should contribute to platinum outperforming is that silver and gold are trading far further above their costs of production than platinum is.
From Jon Nadler's various pieces on precious metals:
Cash costs for gold production run near $600 while all-in costs are bumping up closer to $900. Silver costs roughly $5 to produce in cash-cost terms. (source)
The aforementioned Standard Bank analytical team notes that “from a cost-of-production perspective, platinum is good value at current levels below $1,550. (source)
With silver trading around $32/ounce, it is selling at over 600% of its cost of production, while gold is trading at over 200% of its cost of production. Platinum, in contrast, is selling at prices close to its cost of production. Obviously, silver and gold's' price can drop a lot further than platinum's price can before producers will start restricting supply due to the losses which would be incurred from continued production.
Overall, I think there is a strong case to be made that platinum is a better value than gold and silver right now. It is trading at low levels relative to other precious metals and isn't trading as far above its cost of production. Investors looking to buy platinum can easily do so with the ETF Physical Platinum Shares (PPLT).