The famous Hope Diamond and the lesser-known Hope Pearl will be reunited for the first time in 150 years when “The Allure of Pearls” exhibition opens Friday at the National Museum of Natural History.

The Hope Pearl, which originally belonged to Lord Henry Philip Hope, is one of the most famous and possibly largest pearls in existence today. The drop-shaped freshwater blister pearl weighs in at 450 carats and measures 2-by-4 inches. It ranges in color from white on one end to greenish gold on the other.

“‘The Allure of Pearls’ brings together a tremendous collection of some of the rarest, largest and most spectacular pearls in the world,” Jeffrey Post, curator of the National Gem Collection at the National Museum of Natural History, said in a statement. “Visitors will be amazed at the great variety of the pearls’ colors and shapes. Each one is beautiful and each has a fascinating story.”

Joining the Hope Pearl is La Peregrina, another famous pearl currently owned by actress Elizabeth Taylor. It was given to her by then-husband Richard Burton in 1969 as a Valentine’s Day gift. It was found in the 16th century off the coast of Panama and was previously owned by Queen Mary Tudor and the Bonaparte family.

The Pearl of Kuwait from the Persian Gulf, the Queen Mary Brooch featuring two large natural pink conch pearls in a 100-year-old setting, and the Survival Pearl, a freshwater pearl reputed to be the world’s largest pink snail pearl, will also be on display, in addition to others.

The exhibition is being held in the museum’s Harry Winston Gallery and can be viewed through Sept. 5.

Free Cab Rides Available for St. Patrick’s Revelers

The Washington Regional Alcohol Program will offer free rides to St. Patrick’s Day partygoers who need a safe way to get home.

The SoberRide program will be offered from 4 p.m. today to 4 a.m. Friday. Residents ages 21 and older can call (800) 200-TAXI for a free (up to $50 fare) ride. Cingular Wireless users can call #-TAXI for the service.

SoberRide is available in the District of Columbia; Montgomery and Prince George’s counties in Maryland; and Arlington, Fairfax, Prince William and eastern Loudoun counties in Virginia.

In addition, a number of Irish bars and restaurants in the District are sponsoring SoberRide. The establishments include The Dubliner Restaurant and Pub on Capitol Hill, and Fado and Irish Channel Restaurant and Pub, both in Chinatown.

Since 1993 alone, WRAP has provided more than 29,000 free cab rides home to would-be impaired drivers.

For more information about WRAP’s SoberRide program, go online to www.soberride.com.

— Amanda Arcuri and Amy Carlile