There were two garments for the High Priest. One was pretty colorful and fancy worn on a normal basis. However on the Day of Atonement or Yom Kippurim, he wore pure white. It is Jewish tradition today to wear white on this day representing purity.
Exodus 28:4, 36, 42 (ISR)
“And these are the garments which they make: a breastplate, a shoulder garment, a robe, an embroidered long shirt, a turban, and a girdle. And they shall make set-apart garments for Aharon your brother and his sons, for him to serve as priest to Me.
“And you shall make a plate of clean gold and engrave on it, like the engraving of a signet: SET-APARTNESS TO YHVH
“And make linen trousers for them, to cover their nakedness, reaching from the waist to the thighs.
The Golden Garments
The golden garments consisted of eight items: tunic, belt, turban, pants, breastplate, ephod, robe, and a golden head plate. Over the white tunic, he put on the sky-blue robe, hemmed with decorative pomegranates and bells which rang as he moved around. Then he put on the ephod, which looked like an apron and was fastened by a long belt. There were two shoulder-straps sewn onto the belt. These straps went behind, up and over the priest's shoulders. Two sardonyx stones were attached at the ends of these straps, on the shoulders. He also put on a breastplate, set with twelve precious stones, one stone representing each of the twelve tribes of Israel. His turban differed from those of the ordinary priests, and had in front a golden plate inscribed "Set-Apart to YHWH".
These were called "golden garments," because gold, the symbol of splendor, appeared in them.
Exodus 28:4, 36, 42 (ISR)
“And these are the garments which they make: a breastplate, a shoulder garment, a robe, an embroidered long shirt, a turban, and a girdle. And they shall make set-apart garments for Aharon your brother and his sons, for him to serve as priest to Me.
“And you shall make a plate of clean gold and engrave on it, like the engraving of a signet: SET-APARTNESS TO YHVH
“And make linen trousers for them, to cover their nakedness, reaching from the waist to the thighs.
The Golden Garments
The golden garments consisted of eight items: tunic, belt, turban, pants, breastplate, ephod, robe, and a golden head plate. Over the white tunic, he put on the sky-blue robe, hemmed with decorative pomegranates and bells which rang as he moved around. Then he put on the ephod, which looked like an apron and was fastened by a long belt. There were two shoulder-straps sewn onto the belt. These straps went behind, up and over the priest's shoulders. Two sardonyx stones were attached at the ends of these straps, on the shoulders. He also put on a breastplate, set with twelve precious stones, one stone representing each of the twelve tribes of Israel. His turban differed from those of the ordinary priests, and had in front a golden plate inscribed "Set-Apart to YHWH".
These were called "golden garments," because gold, the symbol of splendor, appeared in them.
Leviticus 16:4 (ISR)
“He should put on the set-apart linen long shirt, with linen trousers on his flesh, and gird himself with a linen girdle, and be dressed with the linen turban – they are set-apart garments. And he shall bathe his body in water, and shall put them on.
The White Garments
Only on the Day of Atonement, Yom Kippurim would the High Priest wear the white garments: tunic, belt, turban and pants. This signifies that the High Priest (Cohen HaGadol) came before YHWH within the Most Set-Apart Place humbly and simply. He did not come in the outward splendor of gold and rich colors, but in pure white. Furthermore, white is the color of forgiveness, and forgiveness is what the High Priest is seeking for himself and all Israel as he came before the Ark.
Only on the Day of Atonement, Yom Kippurim would the High Priest wear the white garments: tunic, belt, turban and pants. This signifies that the High Priest (Cohen HaGadol) came before YHWH within the Most Set-Apart Place humbly and simply. He did not come in the outward splendor of gold and rich colors, but in pure white. Furthermore, white is the color of forgiveness, and forgiveness is what the High Priest is seeking for himself and all Israel as he came before the Ark.
There was also the shoulder stones and the breasplate to represent the 12 Tribes of Israel.
Exodus 28:9-12 (ISR) "And you shall take two shoham stones and engrave on them the names of the sons of Yisra’ĕl, six of their names on one stone, and the remaining six names on the other stone, according to their birth. "With the work of an engraver in stone, like the engravings of a signet, engrave the two stones with the names of the sons of Yisra’ĕl. Set them in settings of gold. "And you shall put the two stones on the shoulder pieces of the shoulder garment as stones of remembrance for the sons of Yisra’ĕl. And Aharon shall bear their names before יהוה on his two shoulders, for a remembrance.
Exodus 28:15-21 "And you shall make a breastplate of right-ruling, a work of a skilled workman, like the work of the shoulder garment. Make it of gold, of blue and purple and scarlet material, and fine woven linen. "It is square, doubled, a span its length, and a span its width. "And you shall put settings of stones in it, four rows of stones: The first row is a ruby, a topaz, and an emerald; and the second row is a turquoise, a sapphire, and a diamond; and the third row is a jacinth, an agate, and an amethyst; and the fourth row is a beryl, and a shoham, and a jasper. They are set in gold settings. "And the stones are according to the names of the sons of Yisra’ĕl, twelve according to their names, like the engravings of a signet, each one with its own name, for the twelve tribes.
Also on the breastplate was the Urim and the Tummin. These were for "right-ruling". I was told that they were "Yes" or "No" stones and if the answer was Yes, that the Yes stone would glow if No then the No stone would glow. I can't find this is Scripture, the glowing part, so it may be Jewish tradition.
Exo 28:30 "And into the breastplate of right-ruling you shall put the Urim and the Tummim, and they shall be on the heart of Aharon when he goes in before YHWH. And Aharon shall bear the right-ruling of the children of Yisra’ĕl on his heart before YHWH, continually.
I hope this helps you get a visual of what the Priestly garments looked like. I will later post pictures for the Tabernacle (Mishcan) and the Temple (Hekal) and the elements that were involved.
Blessings.