Macella O'Neill and her partner Charles White started Diamond
Mountain Stables (DMS) in 1983, returning to their hometown of Calistoga after
they had both gone to college. Macella graduated from UC San Diego with a
double major in history and biology and was poised to continue her education,
but decided to take a "short break" and indulge her love of horses
and start DMS w/Charlie and his love of business. The rest, as they say, is
history!
It's been quite a journey from local 4-H leader to World Cup
competitor. Along the way Macella has coached year end winners in every
division: ponies, equitation, hunters, jumpers and won medal finals as well as
put students on the highly competitive Zone 10 Young Riders teams. Enormously
popular as a clinician, Macella has taught clinics all over the world as well
as judging when time allows.
In an effort to participate in the industry that has given her so
much, Macella has been the president of the NorCal Hunter Jumper Association
for several years and was the NorCal liaison to the Pacific Coast Horse
Association and an AHSA rep as well. For fifteen years Macella, and the entire
gang @ DMS (really Charlie!) ran the enormously successful Napa Valley Classic
horseshow which raised a great deal of money for local charities and no doubt
is one of the reasons that Macella was named as one of the outstanding women of
Napa County in 1999.
But Macella's true claim to fame is in the saddle where she has
won in every division but specializes in developing young horses into top
jumpers. In California, O’Neill has been the leading NorCal jumper rider five
times, (finishing second three times, including 2009). At the
national and international level Macella has been named Leading Rider at the
HITS winter desert circuit, won numerous Grand Prixs, including one in Germany
and last year (2009) qualified Melanie Rapp's beautiful grey,
"Incandescent" to compete at Las Vegas in the National Grand Prix @
the World Cup Finals.
This year Macella has an exceptionally exciting group of horses to
ride in addition to DMS's best group ever of junior and amateur
competitors. It just keeps
getting better.
Longtime Calistoga resident, Charles White has been running the Charles White Hay Sales out of Diamond Mountain Stable for the past 25years. He got into the business because hay sales were a natural adjunct of the horse stable. White said, “I like being involved in the animal side of the ag business. I like being involved with people connected to the earth.”
When he is not managing the hay business, White works with his partner, Macella O’Neill on the DMS horse training and show business. White is involved in all aspects of this business. He hauls horses to shows throughout northern and southern California, as far east as the Kentucky Horse Park and even to Spruce Meadows in Calgary, Canada. White also coaches O’Neill at home and in the warm up arena at the shows as well as helps train the many clients who attend horse shows.
Born and raised in Germany. Maryanne began an intensive riding education. She came to the US in 1984 and is fluent in German. BS Zoology Ohio University
Training, teaching, showing, riding, judging in Dressage, Vaulting (started the only accredited vaulting program in North Carolina), Western pleasure, Reining & Three Day Eventing. Further top work experience in breeding, rental string management, fox hunting, galloping for the race track and summer camp programs. Familiar with most breeds including Paso Fino's.
Instructor for University accredited courses as well as head coach of the IHSA programs of Ohio University (co-founded the program), Duke University and University of North Carolina (wrote the Beginners Handbook to Riding). Taught up to 350 students a week. Duke University Memorial Award for coaching excellence 1989.
Primary training and competition focus in dressage from unbroke horses through Grand Prix. Owned and operated dressage business 1991-2001. Continued education included USDF training symposiums, biomechanics seminars and ongoing clinics with riders such as Steffen Peters, Lilo Fore and Jan Ebeling as well as annual trips to Germany. Many Northern Alliance, CDS and USDF Championship wins and placings.
European import business started in 2002, working for and with DMS since 2003
No top barn can succeed without an excellent head groom and at DMS it has been Gelacio for the past 16 years. Gelacio' quiet calm way is a welcome balm to both horses and people and his organiztional skills and perfectionist tendencies are essential to top performances.
Marcie Hall was born and raised in the “outskirts” of Napa
She describes her
connection with horses as a “balance between fascination and pure love”. Her
first memory of horses was on her maternal grandparent’s ranch outside of
Calistoga. Years later, when her oldest sister
Katie opened a stable, it seemed natural that Marcie join in her endeavor.
In 2006 Charles White met Marcie while delivering a load
of hay to Katie & Marcie’s stables. Soon afterwards, Marcie began working
part time at Diamond Mountain Stables (DMS)
In
2008 Katie & Marcie moved their horses to DMS, where they now provide
beginners riding experiences and compete successfully at local shows.
In
February 2010 Marcie became a full time employee at DMS.
In
addition to co-facilitating beginning lessons, she has taken on the office
manager position with “Charles White Hay”; assists with horse grooming and
veterinarian care; is apprenticing under professional trainer rider Macella
O’Neill’s hunter jumper program; and is developing an ever increasing knowledge
of the horse show industry.
Jesse was born in Santa Cruz to a dad who was a cattle rancher and whose parents put on annual rodeos at their ranch. Jesse shared a pony with her sister until she was three when she got her own stubborn, barn-sour mare who she barrel raced on.
She was competitive in rodeos and gymkhanas throughout her childhood. At 12, Jesse spent her summers working with a cow horse trainer in Fernley, NV. She learned how to start young horses and before she was 14, Jesse had trained and sold her first horse.
For the past year, Jesse has been working with an equine veterinarian in Reno and is pursuing her goal to become a certified veterinary technician. Jesse was offered the opportunity to ride with Macella and learn the ways of the show jumping world, while riding along with Dr. Claudia Sonders two days a week.
Jesse feels fortunate to be working with the DMS team and is looking forward to everything that she will learn from being here this summer.
Macella O'Neill and her partner Charles White started Diamond
Mountain Stables (DMS) in 1983, returning to their hometown of Calistoga after
they had both gone to college. Macella graduated from UC San Diego with a
double major in history and biology and was poised to continue her education,
but decided to take a "short break" and indulge her love of horses
and start DMS w/Charlie and his love of business. The rest, as they say, is
history!
Longtime Calistoga resident, Charles White has been running the 
Born and raised in Germany. Maryanne began an intensive riding education. She came to the US in 1984 and is fluent in German.
No top barn can succeed without an excellent head groom and at DMS it has been Gelacio for the past 16 years. Gelacio' quiet calm way is a welcome balm to both horses and people and his organiztional skills and perfectionist tendencies are essential to top performances. 
Marcie Hall was born and raised in the “outskirts” of Napa
She describes her
connection with horses as a “balance between fascination and pure love”. Her
first memory of horses was on her maternal grandparent’s ranch outside of
Calistoga. Years later, when her oldest sister
Katie opened a stable, it seemed natural that Marcie join in her endeavor.
Jesse was born in Santa Cruz to a dad who was a cattle rancher and whose parents put on annual rodeos at their ranch. Jesse shared a pony with her sister until she was three when she got her own stubborn, barn-sour mare who she barrel raced on.