Silver prices were slipping Tuesday, causing technical analysts to fret that the upward price trend in the metal may be in jeopardy.

Benchmark futures contracts for silver bullion were shedding 7 cents at $11.84 an ounce in recent New York activity. The

iShares Silver Trust

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exchange-traded fund, which holds bars of silver bullion, was losing 1.2%.

"The breakdown of the silver price over the last month has been very disappointing," says Adolfo Rueda, a technical analyst at Natixis Bleichroeder in New York.

technical analysts make predictions about future price moves based on the visual patterns represented on historical charts. Spot prices for silver have rallied from under $9 an ounce in January 2006, but lately fell back from a recent high of $13.34 an ounce in late July.

Rueda says the failure of prices to hold above $10 an ounce would be particularly bearish.

Silver producers

Coeur d'Alene Mines

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and

Hecla Mining

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were both losing more than 1%.

Shares of

Silver Wheaton

(SLW)

were edging higher by 0.1% recently.

In other metals, copper prices were slipping a penny at $3.16 a pound, while gold prices were edging $2.20 higher at $668.70 an ounce.

The

PowerShares DB Base Metals

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ETF was down 0.1%. The

streetTracks Gold Shares

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ETF was barely changed.

Elsewhere, prices for sugar were lower by 1.1% at 9.3 cents a pound, while coffee prices were off a penny at $1.18 a pound.

Wheat prices were rallying 0.7% at $6.96 a bushel, and soybeans were trading for $8.33 a bushel, also up 0.7%.