Since the days of great painters like Jan Van Eyck and Velasquez, artists have used mirrors within their paintings to multiply images, just as they have introduced glass windowpanes, as a source of light, shadow and atmosphere. Long before that, stones were carved by sculptors and cut into building blocks by architects.

In that sense, Yuri Schwebler's new show of sculpture at Diane Brown, 2028 P St. NW, is traditional, for it uses these old artistic devices exclusively -- mirrors, glass and stones. In every other way, however, his work is a measure of how art has changed though its basic vocabulary has stayed the same.

For these new sculptures consist not of painted or carved "images," but of the real thing -- rectangular slabs of plate mirror and plate glass left unembellished as they were when they left the factory; and rocks and stones, large and small, left just as they were when they were picked up on the beach or in the woods.

It is what you would expect from Washington's leading sculptor in the postconceptual, postminimal mode -- an artist perhaps best known here for making a sundial out of the Washington Monument by plowing radial lines in the surrounding snow. Since then his plumb-bob pieces have been his hallmark.

Schwebler has now transformed a new set of very minimal materials into elegant, beautiful ensembles that become evocative and highly expressive pieces of contemporary sculpture.

For example, one large piece on the ground floor, titled "Seven-Thirteen," consists only of seven tall, overlapping sheets of glass, each angled differently to the wall, and each held in place by a large rock. The rocks -- all river stones -- set upon mirrors call up the water that has worn them into concentric rings. The piece sparkles and changes constantly as the viewer moves around it.

Another large work upstairs, called "Lean-To," is similarly formed by tall rectangles of mirror and glass leaning against the wall, each held in place by large and beautiful rocks -- this time sandstones which modulate in color from pink into gray. The basic module is the same, though in different configurations.

This module, in its endless variations, is, in fact, the subject and core of this entire cycle of work, which also includes several small, boxed wall-hung pieces. In his last show, Schwebler began encasing his earlier plum-bob pieces in wooden boxes, but that cycle was a summing up, while this one points to fresh, new possibilities for the future. These current works are far more lively and pleasing, though they obviously grew out of the mirror-box idea introduced in his last exhibition.

Though choices are difficult in a show of such consistenly high level, "Crystal Palace" is particularly beautiful, with small triangular pieces of quartz holding up bits of mirror that wind into the infinity of the mirrored sides of the box. Color is inroduced in the interior of several boxes, but it is most affecting in the subtle gradations of the colored stones. Anyone who has ever picked up a stone on a beach will no doubt share at least some of the myriad pleasures in these works which so successfuly harmonize seemingly opposed natural and manmade forms.

The show continues through March 3.

At first glance, the works of James Crable at Gallery K, 2032 P St., NW appear to be all-over patterns of some sort. Closer inspection reveal them to be photo-collages made from series of color photographs all made at the same architectural site, but with different people passing. With the FBI Building as backdrop, for example, different figures walk by creating various patterns, while a New York subway entrance provides a dramatic, distorting proscenium as figures emerge and descend. A certain random scenario emerges as the works are explored at close range.

Though this sort of patterned serial photo-collage is rampant in the wake of earlier pieces in this genre by New York artist Ray Metzger, Crable does what he does well, and often to provocative effect. Through Feb. 24.

From the very first impression in Howard McKenzie's show of color etchings, just opened at Wolfe St. Gallery, 1204 31st St., NW. the influence (if not the very visage) of his former teacher, famed printmaker Mauricio Lasansky, is all-pervasive.

At the same time, McKenzie has learned his craft well, and has been working hard to develop his own figurative imagery, often based on theatrical, cabaret, fantasy or circus themes, and always in a dreamlike style that recalls Redon. Among other subjects, which range from Marlene Dietrich to Mickey Mouse, McKenzie's own invented "Fair Haired Beauty" and "Gold Digger" are particularly amusing and original. Prints are most reasonably priced. Through March 3.

Although the Women's Caucus for art has left town, Washington galleries are still resounding from their presence here last week. More than 40 exhibitions remain in their wake, and the largest and most important of them all is Women Artists in Washington Collections, which continues at the University of Maryland Art Gallery through Feb. 25. Anyone interested either in good art or in revelations should not miss it.

Curator Josephine Withers, in her admirable catalogue essay, makes her purpose clear: "If a work of art enters a public museum, there is a fair chance that it will be preserved, but no necessary guarantee that it will be kept alive. In order to reveal itself, a work of art must be seen."

Thus Withers has scoured local museum reserve collections and has come up with an astonishing array, ranging from an 18th-century pastel portrait by French artist Adelaide Labille-Guiard through 19th-century embroidered pictures and quilts to paintings by Romaine Brooks, Catherine Murphy, Helen Frankenthaler, Isabel Bishop, and Washington's own Ann Truitt and Rebecca Davenport. Also included is a show-within-a-show of photographs first assembled in 1900 by Washington photographer Frances Benjamin Johnston, which traveled to St. Petersburg and Paris. A major catalogue accompanies the exhibition.

Other exhibitions of work by women artists continue to pop up everywhere -- and from everywhere. H.R.H. Princess Wijdan Ali of Jordan, the first woman in that country's foreign service, is showing paintings at the Middle East Institute, 1761 N St. NW, while Russian-born Bulgarian artist Natalia Klyova is having her first one-person show at Amerope-Hemus Art Gallery in Les Champs at the Watergate.

Young Klyova's paintings, brilliant with color, show a strong influence of a Chagall and Picasso at the moment, as she struggles to get past these masters to a style of her own. In fact "Flying My Kite" and another "View of Washington" show great spirit in an expressionistic style which seems more her own. The show closes Feb. 15, to be followed by the work of another Bulgarian-born woman painter, Emilia V. Tepavicharova, who now lives in New York. Amerop-Hemus specializes in showing new work by Bulgarian artists.

And lest they go unnoticed, two smaller shows organized in connection with the Women's Caucus for Art continue through the month and should be seen. They are "Label: Women," a juried area exhibition now on view in 800 Independence Avenue, and "Black Women in the Visual Arts: A Tribute to Lois Mailou Jones" at the Martin Luther King Library. "Women, YES" also continues at Touchstone Gallery, 2130 P St. NW, through Feb. 17.

This is the final weekend for "Open City," a group of "open studios" in downtown Washington organized by the Washington Project for the Arts. Times and locations, published earlier here, can be obtained at W.P.A.