Slumping precious metal values have weighed heavily on the FTSE 100‘s (INDEXFTSE: UKX) specialised miners like Randgold Resources (LSE: RRS) and Fresnillo (LSE: FRES).

Their share values crumbled 19% and 17% respectively during August as gold and silver prices fell. The yellow ‘safe haven’ asset touched its cheapest since late June at the end of the month, to hit around $1,310 per ounce, and back from the two-year peaks punched earlier in the summer as speculation over a Federal Reserve interest rate hike gained traction

Some retracement isn’t a surprise anyway given Randgold and Fresnillo’s heady ascent in 2016. The stocks have exploded 71% and 123% since the start of the year as a maelstrom of geopolitical and macroeconomic worries has fuelled precious metal prices.

But I believe there’s much more fuel in the tank for both stocks to regain their upward momentum. The fate of the UK economy, not to mention that of Europe and the broader global economy, is very much up in the air following June’s Brexit referendum. And patchy manufacturing data from China this week has amplified concerns over economic cooling in the engine room of Asia.

A rate rise across the Atlantic, and subsequent advance in the US dollar, could put the precious metals segment under fresh pressure in the weeks ahead. But Fed action is far from a foregone conclusion. And I reckon investor appetite for Fresnillo and Randgold could ignite again should global economic indicators keep on disappointing.

Drugs diver

Healthcare giant Hikma Pharmaceuticals (LSE: HIK) also saw its share price take a pasting in August, the stock losing 19% during the course of the month.

Hikma collapsed at the start of August after downgrading full-year estimates for its Generics division, as slower approvals for new products at its West-Ward Columbus unit weighed on revenues. The drug giant now expects core operating profit from its entire generics suite to range between $30m and $40m in 2016, down from the $46m profit of a year ago.

Research and development problems are part and parcel of the pharmaceuticals business, where extended testing work can result in rapidly-rising capex costs and huge revenues losses. But I believe Hikma — bolstered by exciting acquisitions like West-Ward Columbus and Roxane Laboratories — could still deliver sterling gains in the years ahead as healthcare investment grows around the world.

Having sad that, I believe those seeking exposure to the pharma space may be better with big-cap peers GlaxoSmithKline and AstraZeneca, where news surrounding up-and-coming products has been far more encouraging, and which both deal at a hefty discount to Hikma.

The latter deals on a forward P/E rating of 24.6 times versus 15.7 times at AstraZeneca and 16.7 times at GlaxoSmithKline. I reckon these valuations leave these firms in much less danger of a severe correction than Hikma in the event of disappointing R&D news.

Think Foolishly

Times of macroeconomic uncertainty like these mean that picking the 'right' stock can be more difficult than usual.

This is why The Motley Fool's crack team has come up with this wealth creation report highlighting how YOU can make a fortune by picking the right stocks, timing your trades correctly and going against the herd.

Click here to download our EXCLUSIVE 10 Steps To Making A Million In The Market report. It's 100% free and can be sent straight to your inbox.

Royston Wild has no position in any shares mentioned. The Motley Fool UK owns shares of and has recommended GlaxoSmithKline. The Motley Fool UK has recommended AstraZeneca and Hikma Pharmaceuticals. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors.