Alexandria last night become the first. Washington area suburban jurisdiction to pass tough new regulations designed to curb the increasing number of burglaries prompted by soaring gold and silver prices.

The City Council unanimously passed ordinance requiring secondhand dealers to keep gold, silver and other items made of percious metals for at least 15 days before selling or melting them. The ordinance also requires dealers to obtain operating permits from police, to keep detailed records of each transaction, noting the seller's name, physical description, and a description of his car. Dealers will be required to make daily reports of purchases to police, and to permit police to inspect their property at will. o

Other aspects of the ordinance, sponsored by Councilman Carlyle C. Ring Jr. (R), prohibit dealers from buying goods from juveniles under 18 and from buying goods from which the serial number or other indentification has been obliterated.

"This should help" lower city's worsening burglary rate, Alexandria Commonwealth's Attorney John E. Kloch told the council last night.

Burglary in the city last year increaded by more than 20 percent, and police had complained they were helpless to stop thieves from quickly selling stolen property to some second-hand dealers.

Officials in other suburban jurisdictions are considering similar legislation in the belief that break-ins and thefts have been accelerated by the skyrocketing prices for precious metals. Sterling silver currently sells for about $15 an ounce and 10-karat gold brings about $300 an ounce.

Montgomery County is considering legislation that, among other things, would require dealers to hold goods for 15 days. Fairfax and Prince George's counties are considering placing a minimum five-day holding period on dealers who buy precious metals.

The District of Columbia already has a law requiring dealers to hold goods for 15 days. That law is being challenged in court by dealers.

Some precious metals dealers have argued that they are put at an unfair competitive advantage when they are forced to hold goods for an arbitrary time rather than being allowed to sell the items quickly to take advantage of favorable market prices.

Dealers also have complained it is dangerous for them to keep precious metals on hand in view of the threat of robbery.

Violation of the Alexandria ordinance carries with it a 12-month jail sentence or $1,000 fine on conviction.